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\pstTriangle[PosAngleB=-90, PosAngleC=90]% (1,1){A}(-1,-1){B}(-2,1){C} \pstMiddleAB{A}{B}{C'} \pstMiddleAB[PosAngle=90]{A}{C}{B'} \pstMiddleAB[PosAngle=180]{C}{B}{A'}