A workbench for inventing calendars and seeing how they behave. Define months, year types and intercalation rules; watch the wall-grid, cycle and drift update live; and read the design-space analysis — mean year as an exact fraction, accuracy in min/yr and d/century, the continued-fraction convergents your cycle sits among, and automatic detection of named systems (Julian, Gregorian, Neap, Milesian…). Built by fusing two prototypes below.
d = y + a + b/n + …, continued fractions, named-system detection — and
rich visualizations (radial clocks, heatmap, error spikes, converter, solstices).
→ open proto