function [ state ] = sample_free_states( state_limits, obstacles, radius)
not_done = true;
while not_done
    state = rand(size(state_limits,1), 1);
    state = state.*(state_limits(:,2)-state_limits(:,1))+state_limits(:,1);
    not_done = ~is_state_free(state, state_limits, obstacles, radius);
end
end