function [value,isterminal,direction] = catmouseevents(t, x, vm)
tol = .00001;
% detect when distance |cat - mouse| = tol
value = (1 - vm*t - x(1))^2 + x(2)^2 - tol^2;
isterminal = 1; % Stop the integration
direction = 0; % Detect crossing zero from either direction
