Transformations in the complex plane

Written by H. A. Verrill and I. Breeze, 2020/21.

Program for exploring transformations of the complex plane, drawing fundamental domains for subgroups of PSL(2,Z). Works on safari, with mouse.


Farey Symbol: will appear here if a group is chosen


  • Matrix:
    M =

Domains for SL2(Z):
Domain for
change group: Γ0 ()

change polygon by vertex
Vertices: pj = (a + ib)/c
j a b c