A fastener for connecting two layers of stacked plate-like elements includes first through fifth sections. The first section is configured to abut against an outer side of the first plate-like element. The second section has a height corresponding to a thickness of the first plate-like element and is receivable in a through hole of the first plate-like element. The third section is configured to pass through the through hole of the first plate-like element in a first orientation, and a first side of the third section is configured to abut against an inner side of the first plate-like element in a second orientation, and a second side of the third section is configured to abut against an inner side of the second plate-like element. The fourth section is configured to pass through the through hole of the first plate-like element in the first orientation, and the fourth section is receivable in a through hole of the second plate-like element. The fifth section is configured to hold the second plate-like element.