That is true whenever the piece will be matching two different sides, you'll have to pull it apart on at least one line (column/row). However, since the pieces

That is true whenever the piece will be matching two different sides, you'll have to pull it apart on at least one line (column/row). However, since the pieces slide together instead of locking together I don't see that as much of a problem. The bigger problem would be pulling them out of the sack at 'random' :D