List of 21 unit vectors:
(You can copy and paste them into the DW-MRI signal generator.)

0.1639 0.5115 0.8435
0.1176 -0.5388 0.8342
0.5554 0.8278 -0.0797
-0.4804 0.8719 0.0948
0.9251 -0.0442 0.3772
0.7512 -0.0273 -0.6596
0.1655 -0.0161 0.9861
0.6129 -0.3427 0.7120
0.6401 0.2747 0.7175
-0.3724 -0.3007 0.8780
-0.3451 0.3167 0.8835
0.4228 0.7872 0.4489
0.0441 0.9990 0.0089
-0.1860 0.8131 0.5515
0.8702 0.4606 0.1748
-0.7239 0.5285 0.4434
-0.2574 -0.8032 0.5372
0.3515 -0.8292 0.4346
-0.7680 -0.4705 0.4346
0.8261 -0.5384 0.1660
0.9852 -0.0420 -0.1660