An electric pencil sharpener with delay function includes a motor, a drive assembly, a gear assembly and a cutter assembly. The drive assembly includes a connecting rod, a drive shaft and a start trigger, a stop trigger, and a thrust plate. The connecting rod is moved backward to drive the start trigger to trigger the motor, and synchronously rotated with the cutter assembly; the stop trigger is provided with a teeth structure and a friction structure respectively. The thrust plate is rotated or moved to push against the drive shaft, so that the connecting rod continues to move backwards until the bulge portion engages with the teeth structure, and the ring portion matches with the friction structure, thereby actuating the stop trigger to move to trigger an action of the stop switch of the motor.

A compass, comprising: a housing; a control dial; a drive gear, wherein the drive gear is attached to the control dial; an adjustment gear, wherein the adjustment gear is in in communication with the driver gear; a first gear portion in communication with the driver gear; a second gear portion in communication with the adjustment gear; and a plurality of wheels, wherein the wheels are secured to the first and second gear portions.

The tracing instrument, such as a ruler, set square or protractor, includes a main body with one or more lateral tracing elements. The tracing instrument includes sliding systems and gripping systems. The sliding systems include displacement devices chosen from among translation, rotation, deformation with respect to the main body and devices to facilitate movement/displacement of the tracing instrument. The tracing instrument can be made in several blocks. The main body associated with the gripping systems and the lateral tracing elements associated with the sliding systems are separated blocks. The main body is operable by pressing to perform a gripping. The tracing instrument can be for the school environment, in particular for children suffering from dyspraxia, however it can be extended to other uses.

A compass, comprising: a housing; a control dial; a drive gear, wherein the drive gear is attached to the control dial; an adjustment gear, wherein the adjustment gear is in in communication with the driver gear; a first gear portion in communication with the driver gear; a second gear portion in communication with the adjustment gear; and a plurality of wheels, wherein the wheels are secured to the first and second gear portions.

An educational ruler is a protractor, where the protractor can draw and measure angles. The educational ruler includes a planar disk having a semicircular circumference and labeled in scales along the semicircular circumference; a straight line edge connecting two edges of the semicircular circumference; a through hole on the planar disk; a first edge and a second edge extending from the through hole to the straight line edge; a third edge and a fourth edge extending from the semicircular circumference to the straight line edge. The first edge of the through hole of the educational ruler and the second edge of the through hole of the educational ruler intersect at 90 degrees scale of the planar disk to form the first right angle, and the included angle of the first edge of the through hole of the educational ruler and the straight line edge of the educational ruler is 45 degrees.