x1 is a non-polyplet polyform/polyomino/polyabolo/polyiamond (etc.) composed of parts/'tile' polytope x2 arranged in (finite) unified shape/pattern x3 (in which the entirety of sides of polytopes are shared or are not shared at all) in ambient space x4 and subject to rules/restrictions/conditions x5 (implicitly includes the condition of whole sides being shared)
The hyper-edges of the 'tile' polytopes must be shared entirely or not at all with at least one other distinct such 'tile' polytope (should it exist); they cannot be touching only at the corners- the most touch adjacently along the entirety of a side/edge/face/hyper-edge. This obviously restricts which polytopes can be arranged meaningfully in a valid arrangement/pattern (and thus restricts those patterns). See also: pletomino