Give a circle o and make two vertical diameters OA, OB,?

Make point C make OC = 1/40b,?

Let point d ∠ OCD = 1/4 ∠ OCA,?

Draw point E on the AO extension line so that ∠ DCE = 45 degrees.

Step two:?

Make the midpoint m of AE, make a circle with the center of m passing through point A, and this circle intersects with OB at point F,

Then, with D as the center, make a circle passing through point F, and the circle intersects with straight line OA at G4 and G6.

Step 3:?

Crossing G4 makes the OA vertical line intersect with O at P4.

Crossing G6 makes the vertical line of OA intersect with O at P6.

Then take the circle O as the reference circle, the first vertex P4 of the regular heptagon is the fourth vertex, and P6 is the sixth vertex.

With 1/2 arc P4P6 as the radius, all vertices of a regular heptagon can be truncated on this circle.