S1K5E1W4B3A1C3K5
23 points
SKEWBACK is validvalid
a sloping surface against which the end of an arch rests [n SKEWBACKS]
a sloping surface against which the end of an arch rests [n -S]
a sloping surface against which the end of an arch rests [n SKEWBACKS]
a sloping surface against which the end of an arch rests [n -S]