That's a really valid point - I'll be sure to add a line into the tutorial about 1s not being able to be cleared!
The Yellow Dice was really just to illustrate the current connection, showing its an invalid connection I suppose is a side effect of that.
I'm glad you liked the three star system, I hope it gave a great deal of satisfaction when you finally rolled the three star!
A little tip that might help any future attempts: if you can see three sides of the Dice, you know all the others. Opposites sides of the D6 always add up to 7 :)
Thanks for checking the game out!