x3o3o   o3x3o
             
             
    x3o3x    

The dihedral angle at co between octaco and tetaco is arccos(1/sqrt(5)) = 63.434949°, which is 0.176208 of the full circle.

Incidence matrix according to Dynkin symbol

oox3oxo3xox&#x   → height(1,2) = height(1,3) = sqrt(5/8) = 0.790569
                   height(2,3) = 1/sqrt(2) = 0.707107
                   height(12,3) = sqrt(2/5) = 0.632456
(rap || co)

o..3o..3o..    | 4 *  * | 3  3  3  0  0  0  0 | 3  3 3  6  3  6 0 0  0  0  0 0 0 0 | 1 1 3  3  3  6 1 3 3 0 0 0 0 0 | 1 1 3 3 1 0
.o.3.o.3.o.    | * 6  * | 0  2  0  4  4  0  0 | 0  4 1  4  0  0 2 2  2  4  2 0 0 0 | 0 2 2  2  4  2 0 0 0 1 2 1 2 0 | 1 2 1 2 0 1
..o3..o3..o    | * * 12 | 0  0  1  0  2  2  2 | 0  0 0  2  2  2 0 0  2  1  2 1 2 1 | 0 0 0  2  1  2 1 2 1 0 1 2 1 1 | 0 1 2 1 1 1
---------------+--------+---------------------+------------------------------------+--------------------------------+------------
... ... x..    | 2 0  0 | 6  *  *  *  *  *  * | 2  0 1  0  0  2 0 0  0  0  0 0 0 0 | 1 0 2  0  0  2 0 1 2 0 0 0 0 0 | 1 0 1 2 1 0
oo.3oo.3oo.&#x | 1 1  0 | * 12  *  *  *  *  * | 0  2 1  2  0  0 0 0  0  0  0 0 0 0 | 0 1 2  1  2  2 0 0 0 0 0 0 0 0 | 1 1 1 2 0 0
o.o3o.o3o.o&#x | 1 0  1 | *  * 12  *  *  *  * | 0  0 0  2  2  2 0 0  0  0  0 0 0 0 | 0 0 0  2  1  2 1 2 1 0 0 0 0 0 | 0 1 2 1 1 0
... .x. ...    | 0 2  0 | *  *  * 12  *  *  * | 0  1 0  0  0  0 1 1  0  1  0 0 0 0 | 0 1 1  0  1  0 0 0 0 1 1 0 1 0 | 1 1 0 1 0 1
.oo3.oo3.oo&#x | 0 1  1 | *  *  *  * 24  *  * | 0  0 0  1  0  0 0 0  1  1  1 0 0 0 | 0 0 0  1  1  1 0 0 0 0 1 1 1 0 | 0 1 1 1 0 1
..x ... ...    | 0 0  2 | *  *  *  *  * 12  * | 0  0 0  0  1  0 0 0  1  0  0 1 1 0 | 0 0 0  1  0  0 1 1 0 0 1 1 0 1 | 0 1 1 0 1 1
... ... ..x    | 0 0  2 | *  *  *  *  *  * 12 | 0  0 0  0  0  1 0 0  0  0  1 0 1 1 | 0 0 0  0  0  1 0 1 1 0 0 1 1 1 | 0 0 1 1 1 1
---------------+--------+---------------------+------------------------------------+--------------------------------+------------
... o..3x..    | 3 0  0 | 3  0  0  0  0  0  0 | 4  * *  *  *  * * *  *  *  * * * * | 1 0 1  0  0  0 0 0 1 0 0 0 0 0 | 1 0 0 1 1 0
... ox. ...&#x | 1 2  0 | 0  2  0  1  0  0  0 | * 12 *  *  *  * * *  *  *  * * * * | 0 1 1  0  1  0 0 0 0 0 0 0 0 0 | 1 1 0 1 0 0
... ... xo.&#x | 2 1  0 | 1  2  0  0  0  0  0 | *  * 6  *  *  * * *  *  *  * * * * | 0 0 2  0  0  2 0 0 0 0 0 0 0 0 | 1 0 1 2 0 0
ooo3ooo3ooo&#x | 1 1  1 | 0  1  1  0  1  0  0 | *  * * 24  *  * * *  *  *  * * * * | 0 0 0  1  1  1 0 0 0 0 0 0 0 0 | 0 1 1 1 0 0
o.x ... ...&#x | 1 0  2 | 0  0  2  0  0  1  0 | *  * *  * 12  * * *  *  *  * * * * | 0 0 0  1  0  0 1 1 0 0 0 0 0 0 | 0 1 1 0 1 0
... ... x.x&#x | 2 0  2 | 1  0  2  0  0  0  1 | *  * *  *  * 12 * *  *  *  * * * * | 0 0 0  0  0  1 0 1 1 0 0 0 0 0 | 0 0 1 1 1 0
.o.3.x. ...    | 0 3  0 | 0  0  0  3  0  0  0 | *  * *  *  *  * 4 *  *  *  * * * * | 0 1 0  0  0  0 0 0 0 1 1 0 0 0 | 1 1 0 0 0 1
... .x.3.o.    | 0 3  0 | 0  0  0  3  0  0  0 | *  * *  *  *  * * 4  *  *  * * * * | 0 0 1  0  0  0 0 0 0 1 0 0 1 0 | 1 0 0 1 0 1
.ox ... ...&#x | 0 1  2 | 0  0  0  0  2  1  0 | *  * *  *  *  * * * 12  *  * * * * | 0 0 0  1  0  0 0 0 0 0 1 1 0 0 | 0 1 1 0 0 1
... .xo ...&#x | 0 2  1 | 0  0  0  1  2  0  0 | *  * *  *  *  * * *  * 12  * * * * | 0 0 0  0  1  0 0 0 0 0 1 0 1 0 | 0 1 0 1 0 1
... ... .ox&#x | 0 1  2 | 0  0  0  0  2  0  1 | *  * *  *  *  * * *  *  * 12 * * * | 0 0 0  0  0  1 0 0 0 0 0 1 1 0 | 0 0 1 1 0 1
..x3..o ...    | 0 0  3 | 0  0  0  0  0  3  0 | *  * *  *  *  * * *  *  *  * 4 * * | 0 0 0  0  0  0 1 0 0 0 1 0 0 1 | 0 1 0 0 1 1
..x ... ..x    | 0 0  4 | 0  0  0  0  0  2  2 | *  * *  *  *  * * *  *  *  * * 6 * | 0 0 0  0  0  0 0 1 0 0 0 1 0 1 | 0 0 1 0 1 1
... ..o3..x    | 0 0  3 | 0  0  0  0  0  0  3 | *  * *  *  *  * * *  *  *  * * * 4 | 0 0 0  0  0  0 0 0 1 0 0 0 1 1 | 0 0 0 1 1 1
---------------+--------+---------------------+------------------------------------+--------------------------------+------------
o..3o..3x..    ♦ 4 0  0 | 6  0  0  0  0  0  0 | 4  0 0  0  0  0 0 0  0  0  0 0 0 0 | 1 * *  *  *  * * * * * * * * * | 1 0 0 0 1 0
oo.3ox. ...&#x ♦ 1 3  0 | 0  3  0  3  0  0  0 | 0  3 0  0  0  0 1 0  0  0  0 0 0 0 | * 4 *  *  *  * * * * * * * * * | 1 1 0 0 0 0
... ox.3xo.&#x ♦ 3 3  0 | 3  6  0  3  0  0  0 | 1  3 3  0  0  0 0 1  0  0  0 0 0 0 | * * 4  *  *  * * * * * * * * * | 1 0 0 1 0 0
oox ... ...&#x ♦ 1 1  2 | 0  1  2  0  2  1  0 | 0  0 0  2  1  0 0 0  1  0  0 0 0 0 | * * * 12  *  * * * * * * * * * | 0 1 1 0 0 0
... oxo ...&#x ♦ 1 2  1 | 0  2  1  1  2  0  0 | 0  1 0  2  0  0 0 0  0  1  0 0 0 0 | * * *  * 12  * * * * * * * * * | 0 1 0 1 0 0
... ... xox&#x ♦ 2 1  2 | 1  2  2  0  2  0  1 | 0  0 1  2  0  1 0 0  0  0  1 0 0 0 | * * *  *  * 12 * * * * * * * * | 0 0 1 1 0 0
o.x3o.o ...&#x ♦ 1 0  3 | 0  0  3  0  0  3  0 | 0  0 0  0  3  0 0 0  0  0  0 1 0 0 | * * *  *  *  * 4 * * * * * * * | 0 1 0 0 1 0
o.x ... x.x&#x ♦ 2 0  4 | 1  0  4  0  0  2  2 | 0  0 0  0  2  2 0 0  0  0  0 0 1 0 | * * *  *  *  * * 6 * * * * * * | 0 0 1 0 1 0
... o.o3x.x&#x ♦ 3 0  3 | 3  0  3  0  0  0  3 | 1  0 0  0  0  3 0 0  0  0  0 0 0 1 | * * *  *  *  * * * 4 * * * * * | 0 0 0 1 1 0
.o.3.x.3.o.    ♦ 0 6  0 | 0  0  0 12  0  0  0 | 0  0 0  0  0  0 4 4  0  0  0 0 0 0 | * * *  *  *  * * * * 1 * * * * | 1 0 0 0 0 1
.ox3.xo ...&#x ♦ 0 3  3 | 0  0  0  3  6  3  0 | 0  0 0  0  0  0 1 0  3  3  0 1 0 0 | * * *  *  *  * * * * * 4 * * * | 0 1 0 0 0 1
.ox ... .ox&#x ♦ 0 1  4 | 0  0  0  0  4  2  2 | 0  0 0  0  0  0 0 0  2  0  2 0 1 0 | * * *  *  *  * * * * * * 6 * * | 0 0 1 0 0 1
... .xo3.ox&#x ♦ 0 3  3 | 0  0  0  3  6  0  3 | 0  0 0  0  0  0 0 1  0  3  3 0 0 1 | * * *  *  *  * * * * * * * 4 * | 0 0 0 1 0 1
..x3..o3..x    ♦ 0 0 12 | 0  0  0  0  0 12 12 | 0  0 0  0  0  0 0 0  0  0  0 4 6 4 | * * *  *  *  * * * * * * * * 1 | 0 0 0 0 1 1
---------------+--------+---------------------+------------------------------------+--------------------------------+------------
oo.3ox.3xo.&#x ♦ 4 6  0 | 6 12  0 12  0  0  0 | 4 12 6  0  0  0 4 4  0  0  0 0 0 0 | 1 4 4  0  0  0 0 0 0 1 0 0 0 0 | 1 * * * * *
oox3oxo ...&#x ♦ 1 3  3 | 0  3  3  3  6  3  0 | 0  3 0  6  3  0 1 0  3  3  0 1 0 0 | 0 1 0  3  3  0 1 0 0 0 1 0 0 0 | * 4 * * * *
oox ... xox&#x ♦ 2 1  4 | 1  2  4  0  4  2  2 | 0  0 1  4  2  2 0 0  2  0  2 0 1 0 | 0 0 0  2  0  2 0 1 0 0 0 1 0 0 | * * 6 * * *
... oxo3xox&#x ♦ 3 3  3 | 3  6  3  3  6  0  3 | 1  3 3  6  0  3 0 1  0  3  3 0 0 1 | 0 0 1  0  3  3 0 0 1 0 0 0 1 0 | * * * 4 * *
o.x3o.o3x.x&#x ♦ 4 0 12 | 6  0 12  0  0 12 12 | 4  0 0  0 12 12 0 0  0  0  0 4 6 4 | 1 0 0  0  0  0 4 6 4 0 0 0 0 1 | * * * * 1 *
.ox3.xo3.ox&#x ♦ 0 6 12 | 0  0  0 12 24 12 12 | 0  0 0  0  0  0 4 4 12 12 12 4 6 4 | 0 0 0  0  0  0 0 0 0 1 4 6 4 1 | * * * * * 1