This was drawn over a simple horizontal wipe:
; Content type: shape
; Layer:
; Shape: Circle
; Name: polygon
; Number of lobes: 2
; Visible: true
; X offset: 0
; Y offset: 0
; Number of loops: 320
; When transforming shape: smear
; Spin: false
; Grow: false
; Track: true
; Track size: 73
; Track length: -15.95
; Number of loops at each track position: 1
; Track grow: false