Johannes Zumpe (pronounced zumpy) was a maker of the first square pianos, a form of small rectangular piano with a compass of about five octaves. The pianos sounded like mellow harpsichords, and had a damper stop in the left cheek of the case. The action of these little instruments is known as the "English Single" and consists of a little "sticker" simply pushing up on a hammer, while a rod passing through the hith rail lifted up a damper lever. The pianos in Zumpe's style were built from about 1760 to 1800. The square piano had horizontal strings arranged diagonally across the rectangular case above the hammers and with the keyboard set in the long side, it is variously attributed to Silbermann and Frederici and was improved by Petzold and Babcock. ... A grand piano, with the lid up. ... In music, an octave (sometimes abbreviated 8ve or 8va) is the interval between one musical note and another with half or double the frequency. ... Harpsichord in Flemish style; for more info, click the image. ... 1760 was a leap year starting on Tuesday (see link for calendar). ... 1800 (MDCCC) was an exceptional common year starting on Wednesday of the Gregorian calendar, but a leap year starting on Sunday of the Julian calendar. ...