+-----+-----+---+------------+------------+
|   a |   b | i |          x |          y |
+-----+-----+---+------------+------------+
| pan | pan | 1 | 0.34679014 | 0.72680286 |
| eks | pan | 2 | 0.75867996 | 0.52215111 |
+-----+-----+---+------------+------------+

+-----+-----+---+------------+------------+
| aaa |   b | i |          x |          y |
+-----+-----+---+------------+------------+
| wye | wye | 3 | 0.20460331 | 0.33831853 |
+-----+-----+---+------------+------------+

+-----+-----+---+------------+------------+
|   a | bbb | i |          x |          y |
+-----+-----+---+------------+------------+
| eks | wye | 4 | 0.38139939 | 0.13418874 |
+-----+-----+---+------------+------------+

+-----+-----+---+------------+------------+
|   a |   b | i |        xxx |          y |
+-----+-----+---+------------+------------+
| wye | pan | 5 | 0.57328892 | 0.86362447 |
+-----+-----+---+------------+------------+

+-----+-----+---+------------+------------+
|   a |   b | i |          x |          y |
+-----+-----+---+------------+------------+
| zee | pan | 6 | 0.52712616 | 0.49322129 |
+-----+-----+---+------------+------------+

+-----+-----+-----+------------+------------+
|   a |   b | iii |          x |          y |
+-----+-----+-----+------------+------------+
| eks | zee |   7 | 0.61178406 | 0.18788492 |
+-----+-----+-----+------------+------------+

+-----+-----+---+------------+------------+
|   a |   b | i |          x |        yyy |
+-----+-----+---+------------+------------+
| zee | wye | 8 | 0.59855401 | 0.97618139 |
+-----+-----+---+------------+------------+

+-----+-----+---+------------+------------+
| aaa | bbb | i |          x |          y |
+-----+-----+---+------------+------------+
| hat | wye | 9 | 0.03144188 | 0.74955076 |
+-----+-----+---+------------+------------+

+-----+-----+----+------------+------------+
|   a |   b |  i |          x |          y |
+-----+-----+----+------------+------------+
| pan | wye | 10 | 0.50262601 | 0.95261836 |
+-----+-----+----+------------+------------+
