Playground

Difference set workbench

Choose the number of points v, then click points on the circle to build a set D. The bar chart counts how often each nonzero difference a − b (mod v) occurs. D is a (v, k, λ) difference set when every one occurs the same number of times, λ. The link in your address bar keeps the set, so you can share it.

Translates

The translates D + i and D + j of the set above, and how many points every pair of translates shares. For a difference set, every entry off the diagonal is λ.