A method of forming a receiver 130 comprises arranging first structures 120a in a first set 117 and second structures 120b in a second set 119 such that the first structures 120a and the second structures 120b extend within an interior space 136 of the receiver 130 in a direction normal to a longitudinal central axis 112 of the interior space 136. The method further comprises indirectly bonding the first set 117 of the first structures 120a to the second set 119 of the second structures 120b.