Welcome to this edition of Pi Review. You can use the table of contents to quickly jump to the sections you’re interested in. If you’ve discovered other interesting apps or topics you’d like us to cover, feel free to join the discussion in the comments.

New Apps Worth Paying Attention To

While SSPAI has long been committed to discovering and introducing high-quality apps across platforms, there are still many excellent apps—impressive in design, functionality, interaction, and overall experience—that we haven’t yet covered. Some may be long-standing apps, others newly released. We’ll be introducing them to you here.

Powo: Hang a Photo Wall on Your iPhone Home Screen

• Platform: iOS
• Keywords: photo wall, widgets

@ElijahLee: Powo lets you turn a curated collection of photos into a desktop-style photo wall and place it directly on your iPhone Home Screen, so you can revisit your favorite memories without even opening the app.

Creating a photo wall with Powo is very straightforward. The app offers five photo wall templates to choose from. Simply go to the Photos tab, select the images you want to “hang” on the wall, and you’re done. Each photo is framed with a Polaroid-style border, creating a realistic, skeuomorphic look.

The photo wall also comes with a wide range of decorative tools. Beyond photos, you can freely add figurines, stickers, posters, captions, holiday elements, ticket stubs, and more. If you want to add your own custom decorations, that’s easy too. The customization feature allows you to select images from your system library and instantly turn full-size photos into stickers, vinyl records, CDs, and other decorative elements, all with impressively realistic results.

Powo also offers powerful freeform editing and layout options. You can customize the background, colors, and border styles of your photo wall—whether you’re aiming for a felt-board look to suit close relationships, or a dark-toned style better suited for photography showcases. Photos themselves come in multiple styles, with mounting options like push pins or small wooden clips. Any photo or decorative element on the wall can be tapped to adjust its size and hanging angle, making the overall effect feel even more lifelike. If you’re not satisfied with how photos overlap, the app even provides layer-order controls.

Once your photo wall is complete, you can add it to your iPhone Home Screen via a Powo widget and enjoy your memories without opening the app. Of course, you can also export the photo wall within the app to save it locally or share it on social media.

Powo is available for free on the App Store. Most features are usable at no cost, but the free version is limited to creating one photo wall, with up to five photos per wall, and does not support customization features. Upgrading removes these restrictions, with pricing at CNY 3 per month, CNY 18 per year, or a one-time purchase of CNY 38.

Mental Math: Practice Calculations Anytime, Anywhere

• Platform: Android
• Keywords: calculation, mathematics

@Peggy_: After starting work, aside from routine lesson reviews, I’ve found myself using my brain far less than before. For a while, I turned to sudoku to pass the time and keep my mind active. The app I’m introducing today—Mental Math—can serve as another simple tool for mental exercise. Mental Math is a puzzle-style app whose core function is to generate arithmetic problems. Because the types of calculations, difficulty levels, and even the number of questions can all be freely customized, it works both as a brain-training game for adults and as a practical tool for elementary school students to practice their calculation skills.

After opening the app, the first step is to set the practice mode. There are two options: a fixed number of questions or a timed session. The number of questions can be set from a minimum of 10 to a maximum of 50, while timed sessions range from 1 to 5 minutes. Once the mode is selected, you can further design the calculation types. Available operations include addition, subtraction, multiplication, and division. Tapping an operator selects it, and dragging the slider on the right adjusts the difficulty—the larger the number, the more challenging the problems become. Perhaps in order to keep the app lightweight and the difficulty manageable, Mental Math does not offer mixed-operation questions.

After completing the initial setup, you can enter the quiz interface. Once all questions are finished, Mental Math provides feedback on the session, including total time spent, accuracy rate, and a list of questions with their answers. As you complete more exercises, the app aggregates your results and assigns an overall star rating.

Of course, if you’re just looking to do a few quick exercises out of boredom, you can choose Random Mode. The app will automatically generate 20 questions for you. However, since the difficulty in this mode is unpredictable, it’s not well suited for younger students.

So the next time you’re bored and about to open TikTok out of habit, you might consider doing a few calculations instead to keep your mind active. Or if you have children in the lower or middle grades of elementary school who need regular arithmetic practice, Mental Math is also a solid option. For kids, short sessions during spare moments—paired with instant feedback—can be an effective way to train.

You can download and try Mental Math via F-Droid. The app is completely free.

TranscribeX: A Local-First Power Tool for Speech Transcription

• Platform: macOS
• Keywords: text extraction, speech transcription

@化学心情下2: TranscribeX is a speech-to-text transcription tool for macOS. Compared with many transcription apps that rely on online AI models, TranscribeX’s biggest advantage lies in its fully local AI–based approach. All transcription is performed locally, meaning data is stored entirely on your device—ensuring a much higher level of data security and privacy.

In terms of functionality, TranscribeX offers multiple ways to capture audio, including importing audio and video files, recording directly, hooking into recording-type applications, and importing from sources like YouTube. On the model side, it supports Apple’s built-in intelligence models as well as locally downloaded large models. Supported transcription models include Whisper, NVIDIA Parakeet, and others.

To get started, you first need to set the default model and default transcription language under Transcription in the settings. Then return to the main screen and click Import to bring in the audio or video file you want to transcribe. In my case, I selected a two-hour YouTube video. From there, you simply wait in the transcription workspace until the progress bar completes.

TranscribeX splits the audio into multiple time segments and displays the transcribed text by segment. This allows you to start organizing and reviewing the completed portions immediately while the rest of the transcription is still running, significantly improving overall processing efficiency.

Once the transcription is finished, you can export the text in multiple formats, making it easy to continue working with it in other apps. You can also translate the transcribed text into other languages directly within the app.

In testing, transcribing a two-hour audio file took nearly one hour. This may partly be due to the limited performance of my M1 MacBook Air. Even so, overall accuracy was quite high, and the results were well suited for further editing, organization, and summarization.

You can download and use the basic features of TranscribeX for free from the official website. Purchasing the Pro version unlocks additional local models and a range of advanced features. Setapp users can access the paid version of TranscribeX directly.

Artwall: Turn Your Favorite Album Covers into Wallpapers

• Platform: HarmonyOS
• Keywords: wallpapers, music albums

@侧脸君: Artwall is a distinctive wallpaper app on the HarmonyOS platform, built around a clever idea—combining album artwork with wallpapers. With its unique image-processing algorithms, virtually any album cover can be transformed into a stunning phone wallpaper.

The interface and features are extremely simple. Just enter a song title or artist name, tap to view the album-cover wallpapers, and download them. At the moment, Artwall does not support setting wallpapers directly within the app—you’ll need to manually go to your gallery to set the image as your wallpaper.

Although Artwall doesn’t offer an option to choose wallpaper resolution, the resolution is tightly bound to the device being used. If you’re on a Huawei foldable device, the wallpaper resolution and layout saved for folded and unfolded states will differ accordingly.

A good idea naturally sparks the urge to share—especially when it satisfies both “showing off your wallpaper” and “sharing your music taste” at the same time. Just five days after its first release, more and more screenshots of wallpapers generated by Artwall have already begun circulating on social media, highlighting users’ distinctive musical preferences.

You can download Artwall from the HarmonyOS App Gallery. The app is completely free.

Summary Expressive: An AI Summarization Tool with Bilibili Support

• Platform: Android
• Keywords: video summarization

@大大大K: One of the most common uses of AI tools is solving the “TL;DR” problem. Whether it’s a text running thousands of words or images packed with information, AI can easily extract the key points. For video content, however, the mainstream approach still relies on subtitles or transcripts provided by video platforms, converting them into structured text for analysis. This is where a third-party tool like Summary Expressive comes in, feeding platform-generated transcripts to AI models.

Summary Expressive supports multiple content formats, including plain text, web links, images, Word documents, and PDFs. Simply select a file within the app and the AI can quickly generate a summary—tasks that are trivial for modern AI models and don’t even require separate conversion tools. Video summarization is different, though: subtitles and transcripts embedded by video platforms aren’t always standardized like documents or images, which is why Summary Expressive is particularly useful here.

Summary Expressive supports video links from YouTube and Bilibili. After pasting a video link, you can choose the desired length of the summary. In practice, longer summaries aren’t dramatically longer in word count, but they do provide more comprehensive coverage. Medium and short summaries tend to omit some details. The app also offers a text-to-speech feature for summaries, making it ideal for quickly reviewing video content while commuting.

Summary Expressive supports major AI model APIs both domestic and international, including OpenAI, Gemini, and DeepSeek. If you want to summarize Bilibili videos, you’ll need to log in to your Bilibili account in the settings beforehand.

You can now download Summary Expressive for free from GitHub and Google Play. The GMS version requires Google Play Services and downloads image-recognition models online, while the standalone version includes built-in models—choose whichever best suits your needs.

App Updates You Shouldn’t Miss

Beyond brand-new releases, many familiar faces on the App Store continue to iterate and evolve, adding features that are both interesting and genuinely useful. At SSPAI, we aim to help you filter through the updates that are truly worth your attention, so you can quickly stay up to date with the latest moves from apps and their developers.

PhotonCam 1.30 Update: A More Refined Editing Experience for Pro-Level iPhone Photography

• Platform: iOS / iPadOS
• Keywords: mobile photography

@Vanilla: iPhone photography enthusiasts may already be familiar with PhotonCam. While it’s not a household name, this third-party camera app stands out for its rich feature set, polished design, and well-thought-out interactions. At the same time, the developer actively embraces new system features and keeps pace with advances in imaging technology, allowing users to enjoy a more professional photography experience on the iPhone. Recently, PhotonCam rolled out version 1.30—its final major update of 2025—focused primarily on improving the photo-editing experience. Let’s take a look.

First, PhotonCam has updated the HDR display behavior of the focus indicator. More specifically, when adjusting depth-of-field effects on HDR photos within PhotonCam, you can tap the screen to position the focus indicator. In the new version, the area covered by the focus indicator is now rendered with HDR effects as well, making it easier to accurately select the desired focus point.

Second, the new version also refines the behavior of parameters such as fading and brightness adjustments, and introduces a setting that automatically falls back to SDR when the system crops HDR photos under strong lighting conditions. PhotonCam has also improved its launch speed, allowing you to enter shooting mode faster and capture moments more promptly. In addition, a new photo queue feature has been added: when shooting in burst mode or when photos require longer processing times (such as long exposures at night), PhotonCam displays a real-time counter on the gallery button in the lower left corner, indicating how many photos are currently being processed.

Finally, PhotonCam has introduced several new Lock Screen widgets, including options for wide-angle, telephoto, and ultra-wide lenses. However, the developer has clarified that tapping these widgets will only open the app, rather than directly switching to the corresponding focal length. It’s unclear whether this is due to system permission limitations or other design considerations.

That covers the main highlights of PhotonCam’s 1.30 update. If you’re looking for a full-featured third-party photography app on iPhone that balances both shooting and editing capabilities, PhotonCam remains a very solid choice. PhotonCam is available on the App Store under a “free download + in-app purchase” model, with subscription options priced at CNY 12 per month or CNY 68 per year, as well as a one-time lifetime purchase option for CNY 88.

Controller for HomeKit 8.1: Introducing State Logic

• Platform: iOS / iPadOS / macOS / watchOS
• Keywords: smart home, HomeKit

@Snow: Last week, Controller for HomeKit rolled out version 8.1, introducing an all-new States feature. Compared with the native Home app or Aqara’s “Scenes,” which apply a one-time batch change to device states, States enable Controller to support much more complex logical layering, allowing users to build far more flexible automation flows.

Within Workflows, you can create all kinds of state logic. For example: when “Dog at Home” is active, enable the balcony door sensor and alarms; when “Deep Cleaning” is active, pause all motion-triggered lighting rules; when “Guests Visiting,” keep all living room lights permanently on; when “Watching a Movie,” silence all notifications and alarms. On the surface, each individual state may look similar to a scene, but the real power lies in the fact that States not only support logical stacking, they can also be used as triggers, conditions, steps, or stop events within a wide variety of workflows.

For instance, if you’re about to do a deep clean after walking the dog, you can enable both the “Dog at Home” and “Deep Cleaning” states at the same time. This way, the lights won’t constantly change while you’re cleaning, and you’ll still receive notifications if your dog is causing trouble on the balcony. You can also use “Guests Visiting” as a workflow trigger: while turning on the lights to welcome visitors, the system can notify your family members and immediately lock the study door—preventing curious kids from wreaking havoc on your “collection.”

Back in version 7.4, when Hub Mode was introduced, Controller already brought external control links to non-HomeKit users. With this update, the new States feature also supports external control URLs. This means you can use local Shortcuts, or third-party workflow tools like IFTTT, to trigger vacation modes via calendar events or quickly change states from non-Apple devices.

After the 8.0 update, the developer restructured Controller’s pricing model. The original subscription / lifetime purchase option has been renamed Controller Essentials, with the lifetime price remaining unchanged. However, continued access to Hub Mode, Automate Workflows, and the new charting features now requires a Controller Plus subscription. Non-Essentials users must pay CNY 598 per year, while Essentials users can subscribe for CNY 228 per year, both with a 7-day free trial. The price barrier for Controller has clearly risen, so it’s recommended to try it out before deciding whether to commit to further payment.

You can download Controller for HomeKit from the App Store.