主权项 |
1. A mat including a first surface, the first surface having a first axis and a second axis that is orthogonal to the first axis, the mat comprising:
an origin that is positioned along one of the axes; a first indicia that is positioned on the first surface, the first indicia being positioned symmetrically relative to the origin; and a second indicia that is positioned on the first surface, the second indicia being positioned symmetrically relative to only one of the axes. |