Choose a fixed gear, track, and wheel size from the controls.
Choose a Pen mode, then set Pen width and drag a wheel hole to draw curves.
Solid uses your selected ink colour. Spectra Pen paints a rainbow trace based on distance travelled.
Use pinch-to-zoom on touch, mouse wheel to zoom on desktop, and drag empty space to pan.
Use long tap (touch) or right click (desktop) on the canvas to open Fill From Here.
Hide Gear toggles ring and wheel visibility so you can present the clean trace.
Zoom Fit adjusts magnification so the current diagram fits without moving the paper.
Exporting
Export PNG saves the current diagram as a tightly cropped PNG. On touch devices it uses native sharing when available; on desktop it downloads the file.
