split rendering into 2 passes. One to create the rendering data, the other to actually render. This will allow the position/angle of stitches to affect ones that came before it in the chain
specialise singleStitch into chainStitch to hold the behaviour of bending according to stitches above (no op atm)
add transparency to end arrow image
bend chain stitches according to stitches above. Connection lines are broken and icons overlap a bit
log starting pixel ratio