2d day of fools, otherwise one based on theory (1 6 ) a / ? ? ? O ? ?
8a boring thing to pull (4) ? ? ? ?
9d obstacle I'm leaving is triangular structure (8) P ? D ? M ? M ?
12a I won during artists festival 6 )? ? ? A ? I
11a recess never acceptable (4) N ? O ?
21a just open a grate (40 A ? A?