Heikki Lotvonen released Mr. Baby Paint, a simple fullscreen drawing app for toddlers, on December 2026, with about 30 copies sold. The app provides a blank canvas with no menus or toolbars; clicking and dragging the mouse draws directly on the screen. To accommodate imprecise mouse movements, the app uses a Catmull-Rom spline to smooth point samples and stamps a brush texture along the curve at one-pixel intervals, with distance limits for larger brushes. Edge regions of the screen are divided into segments that let the user set brush size and font, select colors, and choose between circle or square brush shapes without using a mouse button. Keyboard shortcuts allow a parent to hold the Alt or Option key to keep the drawing mode active while the child moves the cursor. Other shortcuts enable fill, sand pouring, pause, save, erase, undo, redo, and menu toggle. The flood fill function shares a growth budget of 1000 pixels per frame across all active fills; smaller fills grow faster, causing overlapping fills to produce organic, rippling patterns that resemble a cellular automaton. Lotvonen discovered this behavior while testing rapid successive fills, and he retains the feature because it generates stable or oscillating patterns without blocking drawing. He also created a series of pixel-fattening algorithms to thicken single-stroke bitmap fonts, settling on a method that preserves gaps and details and then refined the result in Aseprite. The resulting fonts appear chunky and legible, and the pipeline can generate various weights from the same source. The app runs on Mac, Windows and Linux and is available for 4.99 USD on itch.io. Lotvonen noted that the CPU-only implementation runs at reasonable frame rates, though a GPU version was attempted and deemed less interesting. He continues to experiment with fill patterns and customization options.