When we changed plate styles in New Zealand - going from a thick alloy plate in black with raised lettering machined off to be shiny,to a thin plate with pressed lettering,white reflecting colour with black lettering.The motorcycle plates came square,and they gave trouble,shattering with the vibration.I fitted 3 to a new XT600 in 3 weeks,until I made a new mount.After a lot of pressure from motorcyclists they reverted to the old rectangular plate.Actually the square plate fitted my old XS1 Yamaha perfectly,so it must have been designed for that shape.