1. The problem statement, all variables and given/known data Find the instantaneous centers of the linkage below. 2. Relevant equations # of ICs = n(n-1) / 2 3. The attempt at a solution From the equation above, there are 4(4-1)/2 = 6 ICs in this linkage. But one thing I don't understand is how there are 4 links when 2 and 3 are welded together to make one piece? And how is the IC of point 2,3 at the center of the circle?