This is a simple toy or exploring the UX of the "hyperbezier" spline.

• Toggle between pen and selection tools with p/v
• 'delete' removes the last added point
• 'auto' points are off-curve points ('control points' or 'handles') that are positioned and updated automatically to maintain constant smoothness through the curve.
• Auto points are drawn with an '×'. Dragging an auto point (or double-clicking it) converts it to a normal point.
• When using the pen tool, click (without modifiers) adds a line from the previous point to the click location.
• Alt+click draws a smooth curve to the click location.