So mad at this puzzle? Note your aim is seven cubes, and distributed evenly amongst them, the 7 different pieces, the 14 bigram clues, and the 7+1 colours...
Each cube will have just one of each colour of the rainbow visible once constructed.
By the way, it's not just the "stomach muscle"/"barium" pair that demonstrates adjacent letters.
A 3x3x3 cube has 26 visible component blocks, a number hopefully familiar to avid puzzlers.
Use the shape, colour, and letter rules to construct seven cubes each communicating a word. Then the centres can come into play.
To get started, here are the seven pieces that include the A block: