10×10 {-1, +1} matrix of maximal determinant

Ratio of |Det R| to Ehlich/Wojtas bound: 1

M=R^TR=R R^T:

10  2  2  2  2  0  0  0  0  0
 2 10  2  2  2  0  0  0  0  0
 2  2 10  2  2  0  0  0  0  0
 2  2  2 10  2  0  0  0  0  0
 2  2  2  2 10  0  0  0  0  0
 0  0  0  0  0 10  2  2  2  2
 0  0  0  0  0  2 10  2  2  2
 0  0  0  0  0  2  2 10  2  2
 0  0  0  0  0  2  2  2 10  2
 0  0  0  0  0  2  2  2  2 10

R:

-++++-++++
+-++++-+++
++-++++-++
+++-++++-+
++++-++++-
+-----++++
-+---+-+++
--+--++-++
---+-+++-+
----+++++-

Notes:

1. Reported to be maximal in [EZ] and in [Wo].
   
2. R is unique up to equivalence [Sm].