Fig. 2

Measurement of the slope angle (α) of bar flipping: α is the angle between Line 2 and Line 3; Line 1 connects the two end holes, and the star sign marks the midpoint of Line 1, while Line 2 represents the star sign to the dorm of the bar. Line 3 represents the star sign where the optimal dorm location should be. This measurement method can be applied to bars inserted either horizontally (A, B) or obliquely (C, D)