"once i have a piece wich is adjacent to the middle corners stay uncheckable. i have to reserve two adjacents if i was doing 1 adjacent+ 1 corner."

i think i understand what you are saying -- if you wish to do a side + a corner, you cannot just reserve both, right?

in the general case, gridcosms logic for reserving is built around the idea of reserving one piece at a time. the fact that an artist can reserve more than one, is really dependent on the other rules. (for example, you can reserve two side pieces at once on a new level.) in other words, its a decision to make folks have to take steps one at a time to build off other pieces. so the same artist making two pieces next to each other has to follow the same logic as if it were two different artists doing those pieces -- one piece is done, then a reservation is made, then the next piece. they chain off each other, regardless of who is making them.

i guess the code could be put in to allow one artists to reserve adjacent pieces (e.g. A1 and B1 on a new level, say). but this way keeps you on your toes! haha i suspect there have been times where someone has snuck in and grabbed the corner pieces another artist was ready for; if i am not mistaken, this has made for some of the "lost gridcosm pieces" that people sometimes put in their artchives.