You can split a rectangle into 2 right-angled triangles. Image caption, STEP 2: Use the compass to draw a circle. Put a dot where the compass rested and use the ruler to draw a horizontal line ...

Draw four lines parallel to each side of the rectangle, 2 cm away. Use a compass to draw rounded corners at D, E, F and G. The straight line of the locus is parallel to the edges of the rectangle ...