I've given up google imaging as not found an example in any pic. In lead dressing of roofs , the term for where you join two lead sheets, in the vertical or roof-slope plane , making specific cuts in the underlaying sheet and the overlaying sheet so the underlaying sheet holds the lower edge of the overlaying sheet that is otherwise not positively held at the top , just an overlap . By twisting up and over at the cuts, repeated every 6 inches or so along the lower edge, giving a sort of butterfly appearance.
Type of brick that was commonly used for garden walls locally, to make a substantial looking garden wall , but hollow. Dimensions 9x4.5x2 inch, laid cvertically on the 2inch faces