170-171: Two PROGRESSIVE DIE ESSAYS in BLACK for the 4¢ and 15¢ values of the UN EXPO `67 ISSUE, denominated in Cdn currency and valid only for postage at the UN Pavilion, printed by the British American Bank Note Co and engraved by C. Graham Yorke, the 4¢ is the outline of the dress only (66x51mm), the 15¢ is the complete internal rectangular design (47x129mm), latter with tiny thin far away from design, otherwise very fine and RARE. (Image)