Three Days With Upside-Down Digits: 0, 1, 6 and 9

References I.J. Taneja, Palindromic, Patterned Magic Sums, Composite, and Colored Patterns in Magic Squares. Zenodo, February 2, 2019, pp. 1-99,  http://doi.org/10.5281/zenodo.2555741http://doi.org/10.5281/zenodo.2555741.