Set of icons with with clock intervals marked. May be useful to represent graphically time periods: 5 minutes (1 hour), 10 minutes (2 hours), 15 minutes (3 hours) and so on until 1 hours (12 hours).
時鐘週期
black、clock、hours、icon、iconset、inkscape、minutes、period、time
黑色、時鐘、小時、圖標、圖標集、Inkscape中、分鐘、期、時間
資料來源：openclipart ( https://openclipart.org/ )