Used by the routines at 52513, 52535, 52566, 52596, 52635, 52717 and 52820 in graphic / room drawing. When the apply-vertical-mirror flag is set, the graphic is reflected in a vertical mirror (i.e. left and right are swapped). When the apply-horizontal-mirror flag is set, the graphic is reflected in a horizontal mirror (i.e. top and bottom are swapped).

Bit	Effect
0	Apply-vertical-mirror
1	Apply-horizontal-mirror
2	Unused
3	Unused
4	Unused
5	Unused
6	Unused
7	Unused