Arity One

Easy sketch app

Free · In‑App Purchases · Designed for iPad. Not verified for macOS.

Open it and draw. Arity turns your strokes into flow charts, class and ER diagrams, or a mind map. Nothing to set up, nothing to learn. Pencil or finger, both just work. Arity opens and you draw. No account, no manual, no setup screen. Pick a diagram type and sketch the way you would on paper. Each type already knows its own notation, so you never have to remember which shape means what or which arrow is allowed where. Arity handles that. You handle the thinking. FIVE DIAGRAM TYPES • Freestyle: a blank canvas, no rules. • Flow chart: Terminal, Process, Decision, I/O, Connector. Break a rule and it says so: only Decision and Connector may branch. • Class diagram: class, abstract, interface; fields and methods; association, aggregation, composition, inheritance, implementation, with multiplicities. Checked against OOP: missing abstract methods, inheritance cycles, interfaces used wrongly. • ER: both crow's foot and Chen, one button apart. • Mind map - official style: one central idea, organic tapering branches, one keyword each, colour inherited down the branch. The diagram argues back when the thinking is wrong. That is the difference between a drawing tool and a thinking tool. APPLE PENCIL Strokes follow your pressure, smooth down to every sampled point. Rest your whole palm on the glass and keep drawing. Two fingers pan and zoom; a second finger undoes whatever the first one just started, so you never nudge a shape by accident. Press and hold stands in for a right click. No Pencil? A finger draws just as well - and Settings lets you decide whether a finger should draw or move the canvas. ONE PROJECT, ONE FILE A whole project lives in a single document with its own folders inside it. It sits in Files under On My iPad › Arity, so backing it up, sending it on, or opening it from iCloud Drive works like any other document. Every change saves itself after a second or so, when you switch diagrams, and when the app goes to the background - written to a temporary file and renamed, so a half-written project is not a thing that can happen. PRESENT ON AN EXTERNAL DISPLAY Plug in a screen and the Present button appears. The external display shows only the diagram while your iPad keeps its toolbar and panels. Not mirroring. ALSO • Arrows bind to shapes and follow them as they move or resize. • Combine shapes with union, intersect, subtract and exclude. • Export PNG from 1x to 4x, transparent or on a colour you choose. • Library: save a selection as an asset and drag it back out later. • Notes, images, groups, undo/redo, minimap. • The entire app is under 5 MB.

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The developer, Kiet Nguyen Tuan, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

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    Accessibility

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    Information

    Seller
    Kiet Nguyen Tuan
    Size
    22.3 MB
    Category
    Productivity
    Compatibility
    Requires iOS 16.0 or later.
    • iPhone
      Requires iOS 16.0 or later.
    • iPad
      Requires iPadOS 16.0 or later.
    • Mac
      Requires macOS 13.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    Languages
    English
    Age Rating
    4+
    In-App Purchases
    Yes
    Copyright
    © 2026 Mikademy Inc.
  • Developer Website
  • Privacy Policy

    • More by Kiet Nguyen Tuan

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