In the 197s, how were the men's boxer shorts with two white side seams cut in the tailor shop?

1. Draw three parallel lines. One parallel line is 3cm apart from the second parallel line, and the second parallel line and the third parallel line are 9cm apart.

2. The front piece is 28 cm wide and the back piece is 3 cm wide. The corners of the back piece should be tilted up one cm, which is determined by the human body structure.

3. Determine the length of the front crotch. Two parallel lines, 5.5cm upward, 5cm to the right, and 2.5cm outward from the middle corner. Draw a round arc after these three points.

4. The back crotch of the back piece is long and lower than the front crotch, which is the third parallel line, five centimeters to the left, and the second parallel line, with the middle corner three centimeters outward. Draw an arc after three points.

5. Draw three parallel lines, the vertex of the back crotch, draw a vertical line of 5.5 cm, and draw another parallel line. This is the fourth parallel line, and the bisector of the drawing angle intersects with the fourth parallel line, and from this point it is connected to the middle seam of the front and rear panels.

6. Leave 3.5cm on the upper part of the trousers for waist, and the waist is connected. Draw the trousers pieces again with a blue pen, which is the trousers pattern. Cut them out and cover them on the fabric for cutting.