Abstract: An instrument for producing on the surface of a given sheet material a given geometric figure having preselected maximum width and length dimensions. A base through a suitable connecting structure carries a marking assembly which is freely movable with respect to the base and which has an inscribing member for inscribing on the surface of the sheet material the given geometric figure. An elongated bar is connected by a lower universal joint to the marking assembly and has an upper end adapted to be manipulated by the operator. Between its ends the bar extends slidably through an upper universal joint which can be adjusted in elevation so as to select a point along the bar about which the latter can be tilted in all directions.

Abstract: A sheet-material feeding unit adapted to be used with a machine, such as a sewing machine, where sheet material is fed past a work station where operations are performed on the sheet material. A supporting structure which is capable of being attached to a part of the machine supports rotary gears having external teeth meshing with internal teeth of a belt which has an external friction surface for engaging the sheet material so as to feed the latter past the work station. This construction prevents slippage between the gears and belt.