rename statics/euler and sync b93 code with main repo

www/statics/euler/Euler_Problem-090_description.md

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+Each of the six faces on a cube has a different digit (0 to 9) written on it;
+the same is done to a second cube.
+By placing the two cubes side-by-side in different positions we can form a variety of 2-digit numbers.
+
+For example, the square number 64 could be formed:
+
+~~~
+  +-------+     +-------+
+ /       /|    /       /|
++-------+ |   +-------+ |
+|       | |   |       | |
+|   6   | +   |   4   | +
+|       |/    |       |/
++-------+     +-------+
+~~~
+
+In fact, by carefully choosing the digits on both cubes it is possible to display
+all of the square numbers below one-hundred: `01`, `04`, `09`, `16`, `25`, `36`, `49`, `64`, and `81`.
+
+For example, one way this can be achieved is by placing `{0, 5, 6, 7, 8, 9}` on one cube 
+and `{1, 2, 3, 4, 8, 9}` on the other cube.
+
+However, for this problem we shall allow the `6` or `9` to be turned upside-down 
+so that an arrangement like `{0, 5, 6, 7, 8, 9}` and `{1, 2, 3, 4, 6, 7}` allows 
+for all nine square numbers to be displayed; otherwise it would be impossible to obtain `09`.
+
+In determining a distinct arrangement we are interested in the digits on each cube, not the order.
+
+ - `{1, 2, 3, 4, 5, 6}` is equivalent to `{3, 6, 4, 1, 2, 5}`
+ - `{1, 2, 3, 4, 5, 6}` is distinct from `{1, 2, 3, 4, 5, 9}`
+
+But because we are allowing `6` and `9` to be reversed, the two distinct sets in 
+the last example both represent the extended set `{1, 2, 3, 4, 5, 6, 9}` for the 
+purpose of forming 2-digit numbers.
+
+How many distinct arrangements of the two cubes allow for all of the square numbers to be displayed?