The trapezoid distortion equalises the lengths of the left-hand and right-hand sides.
Drag the trapezoid distortion at the left-hand side to the required length.
Shorten the trapezoid distortion at the right-hand side to the required length.
Shorten the trapezoid distortion at the left-hand side to the required length.
Drag the trapezoid distortion at the right-hand side to the required length.