The number of crypts at the steady state depends on removal rate of Wnt. (A) The number of crypts at steady state as the removal rate of Wnt is varied for two different initial distributions of Wnt (blue dash line and red solid line). For example, at the same Wnt removal rate of d
= 0.02s−1, there are five crypts (B) or six crypts (C) at steady state starting from two different initial conditions (see Additional file 1: Figure S2 for initial conditions). Other parameters used for the simulation are in Additional file 1: Table S2.