I had a dream last night where I was in a rush - "If I don't turn in a project by Friday, I'm going to fail Physics!" So I got out some lego and built [this fucking thing]. I woke up with the formula already in mind:
C3=IF(COLUMN()>$A$2/ROW(),IF(INT(MOD((ROW()+$B$1)/$A$1,2))=INT(MOD((COLUMN()+$B$1)/$A$1,2)),1,0),INDIRECT(ADDRESS(INT($A$2/COLUMN()),INT($A$2/ROW()))))