DO/EXCL
From Dark Omen Wiki
< DO
ID: "EXCL" block data layout
Also been looking at the EXCL block http://wiki.dark-omen.org/do/DO/PRJ List of all the Maps EXCL items http://img692.imageshack.us/i/pyraexcldifference2.jpg/ B5_01 has 33 EXCL items and B5_01B has 30 maybe something to do with Jewel? (Since B5_01 shows jewel and B5_01B has Temp m3d ploygon to cover the area) and even replaced the EXCL block of B5_01 into B5_01B but did nothing I could detect and didn't crash game. http://img98.imageshack.us/i/pyraexcldifference3.jpg/ B5_01 has a different Value of 04 where as B5_01B had 01 towards the end of its EXCL block.
