X dual

X dualX dualX dualX dualX dualX dual
X dualX dualX dualX dualX dualX dual
X dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dualX dual