•Let A,
B 2 STRUCT[s], and k ¸
0.
•Round
j ¸ 1:
–Spoiler picks a pebble, ai (or b i), i = 1, …, k; if a i
(b
i) was already placed on a structure, then it removes
it; spoiler places the pebble a i
on the
structure A (or b i on the structure B)
–Duplicator
needs to respond by placing pebble b i on B (or a i
on A)