In a cutting device for cutting a round, a transparent substrate is arranged on an object to be cut. A sleeving tube is arranged on the transparent substrate. An end of a transverse rod penetrates through the sleeving rod and extends to over the object. The position of the transverse rod in the sleeving rod is adjusted by a locking member. The other end of the transverse rod is fixed to a cutting assembly. The cutting assembly selectively touches the object. A rotating assembly is combined with the transparent substrate and penetrates through the transparent substrate. When the rotating assembly is pressed to touch the object and the rotating assembly rotates on the object to rotate the transparent substrate, the transverse rod moves the cutting assembly to perform a round-cutting operation on the object or paint a round line on the object.

An apparatus and a process for drawing lines on a sensitive medium are disclosed. The apparatus comprises at least one tool for drawing lines and a programmable device equipped with a touchscreen, the latter being the sensitive medium. The tool for drawing lines includes a compass comprising a first leg having a drawing means installed thereon, the drawing means being able to interact with the touchscreen of the programmable device.

In a cutting device for cutting a round, a transparent substrate is arranged on an object to be cut. A sleeving tube is arranged on the transparent substrate. An end of a transverse rod penetrates through the sleeving rod and extends to over the object. The position of the transverse rod in the sleeving rod is adjusted by a locking member. The other end of the transverse rod is fixed to a cutting assembly. The cutting assembly selectively touches the object. A rotating assembly is combined with the transparent substrate and penetrates through the transparent substrate. When the rotating assembly is pressed to touch the object and the rotating assembly rotates on the object to rotate the transparent substrate, the transverse rod moves the cutting assembly to perform a round-cutting operation on the object or paint a round line on the object.