Hi, Michael... pardon for late reply.

I think something like r99 (turn right 99 degree) or l99 (turn right 99 degree) should be convenient and easy to understand.
That is of course only work with polylines (which record the last point of the line so Moi knows the starting point for left or right)

Also, Michael... IMHO, most of Moi users will expect that the '<' input tab should consider the starting point of line creation rather than 0 is the +X axis (?). The '<' tab almost never used for rotation purpose, isn't it? Or maybe it is just me... ^^

Thank you very much for your attention.