2 Dollars - Elizabeth II 1937 Ariel 1000 Squarefour

This piece belongs to Cook Islands' long-running program of commemorative silver dollars issued under New Zealand's oversight, a revenue arrangement that has funded the territory's government since the 1970s. The subject here is the Ariel Square Four, a motorcycle introduced by Ariel in 1931 with an engine designed by Edward Turner — later the architect of the Triumph Speed Twin — featuring two parallel crankshafts geared together, effectively two parallel twins sharing a common crankcase. The 1937 model year coincided with a significant redesign that moved from an overhead-camshaft to a pushrod valve arrangement.