interactive python(2)

http://www.codeskulptor.org/#user18_xMNnLS4eSr_0.py

timer的使用

http://www.codeskulptor.org/#user18_Gu9Q08s2US_0.py

draw_circle

http://www.codeskulptor.org/#user18_xQk8pGROqn_0.py

 stopclock

http://www.codeskulptor.org/#user18_kN9oIkVZtv_2.py