Tessella

Tessella is an open-source editor for creating, viewing, and manipulating polygon tessellations of the plane. It is designed for Android users who want to explore tilings made from simple regular or irregular polygons. As a Graphics application, it focuses on the visual construction and editing of finite, edge-to-edge tessellations.

Users can add polygons from a palette or insert one by clicking an existing boundary edge. Tessella automatically validates additions so the result remains a proper edge-to-edge finite tessellation. Its editing tools include an eraser for vertices, edges, and polygons, as well as an interior insertion tool. The Add Copy function grows a tiling by welding on a copy of itself under a plane isometry, including translation, rotation, reflection, or glide reflection, with snapping to exact anchors.

Elements can be selected by clicking, colour, or shape, and recoloured with the built-in colour picker. The canvas supports panning, zooming, and rotation for examining and editing a construction from different views. Completed tessellations can be exported to SVG or DOT for use in those formats.

On Android, Tessella is a thin WebView wrapper around the same client-side editor published on the web and as a progressive web app. All processing runs on the device, with no network access, accounts, or trackers. MirrorNest mirrors the official Android build directly on its own storage and scans it for malware before publishing.