toBeziers' start (StraightTo next:ss) = curveSegment start mid mid next : toBeziers' next ss
  where mid = avg [start, next]
toBeziers' start (StraightTo next:ss) = curveSegment start mid mid next : toBeziers' next ss
  where mid = avg [start, next]
toBeziers' start (StraightTo next:ss) = curveSegment start mid mid next : toBeziers' next ss
  where mid = avg [start, next]