Rolling rod of anti-parallelogram mechanisms

Input: pink bar. All the short cranks of various colours have the same length. Short cranks are fixed to the bar of their colour. Two cranks and a blue conrod create an anti-parallelogram mechanism. Grey crank is fixed to the grey base. During motion angles between adjacent bars are not the same (with little differences). In this video for closing the pentagon the pink input bar turns 76.5 deg. (not 360/5 = 72 deg) and the pentagon is not an equiangular one (103.5 or 115 deg., not 108 deg.). A similar mecha