PPC n2 (PPCNTwo) "super iriw, no barriers" { P0:r4=x ; P0:r5=y ; P1:r6=z ; P1:r7=t ; P2:r5=y ; P2:r6=z ; P3:r7=t ; P3:r4=x ; P2:r1=1 ; P2:r2=1 ; P3:r2=1 ; P3:r1=1 ; } P0 |P1 |P2 |P3 ; lwz r1,0(r4) |lwz r1,0(r6) |stw r2,0(r5) |stw r2,0(r7) ; lwz r2,0(r5) |lwz r2,0(r7) |stw r1,0(r6) |stw r1,0(r4) ; locations [0:r1; 0:r2; 1:r1; 1:r2;] exists(0:r1=1 /\ 1:r1=1 /\ 0:r2=0 /\ 1:r2=0) (* Perfect octogon *)