About PiNumpad. Tau

PiNumpad is a free memory trainer for tau (6.28318530717958...), tau, equal to 2π, the ratio of a circle's circumference to its radius. This page shows all the numpad paths for tau, use it to learn the visual patterns before testing yourself in Play mode.

Learn the numpad paths. Study mode shows all numpad paths for the constant at once, laid out group by group. Each group is displayed as a path diagram on the 3×3 numpad grid. You can tap any group's path card to hear the corresponding melody, the audio encoding that accompanies the visual pattern.

Tau simplifies many formulas involving circles and radians, a full turn is τ radians, not 2π. It has a dedicated following among mathematicians who argue it is the more natural circle constant. Scroll through the groups to build a mental map of the full sequence. Tap a path card to play its melody. Use this mode before Learn or Play to orient yourself with the patterns.

PiNumpad is designed for maths students, engineers, programmers, and advocates of the tau manifesto who prefer their circle constants in terms of radius rather than diameter. It runs entirely in the browser with no account, no installation, and no cost. Progress is saved locally using your browser's storage.

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