can't make head or tail of this

"I can't make head or tail of this," he complained.

The Captain had left when he straightened up a few minutes later and said, "I just can't make head or tail of this thing."

The UT can't make heads or tails of this.

"The average participant says, 'I can't make heads or tails of this; tell me where to put my money,' " Mr. Ternoey said.