How to write 14? Important process.

After the square rolled 90 degrees three times on the X axis, A fell on the X axis for the first time 1.

Let the area enclosed by the movement route A and the X axis be S 1, and every 90° S2 and S3.

1, A-A 1, locus of point a: 1/4 circle, R 1= 1,

S 1=S semicircle aa 1b = π r 1 2/4 = π/4.

2. A 1-A2, the locus of point A: 1/4 circle, R2=√2.

S2=S semicircle A 1A2C+S squared ABCD = π R2 2/4 = π/2+ 1.

3, A2-A3, the locus of point A: 1/4 circle, R3= 1,

S3=S semicircle = π R3 2/4 = π/4

Conclusion: S total =S 1+S2+S3=π+ 1.