As every bowler knows, the 7-10 split is the hardest to convert into a spare. In this shot the two pins at the extreme edges of the triangle are knocked down. According to the American Bowling Congress, the 7-10 split has been made about 3,000 times out of a billion or so attempts during any given year. However, a champion bowler named Andy Varipapa used to make the 7-10 split fairly often. His secret: he used two bowling balls.
Varipapa won just about every bowling championship worth having during his career. Just for fun he also tried some trick shots. He developed a few ways to “double-ball” the 7-10 split, but his favorite method was the “double-cross.”
Holding both balls, Varipapa would approach the foul line and let go with his left hand first. Then he let go with his right. He had to do it that way since he was right-handed, and the ball thrown with his right hand would travel faster.
Down the alley, the balls hooked and crossed paths. But Varipapa put a great deal of spin on his balls, so that they crossed again! The ball released from his left hand hit the pin on the left side; the right-handed ball hit the pin on the right.
From The Giant Book of More Strange But True Sports Stories by Howard Liss. Illustrations by Joe Mathieu.
https://en.wikipedia.org/wiki/Andy_Varipapa
I couldn’t find any videos of Varipapa making the balls cross twice on the lane, plus the cross over tricks that I did find all involved the 4, 6 7 and 10 pins. That doesn’t mean Varipapa didn’t do it the way Liss describes–only that I can’t find any video of him doing it that way.