Lenny Fingers is out on the street again, hustling people with his shell games. This time, he's using words.
As you walk by, Lenny grabs you with an enthusiastic smile and shows you two words side-by-side, betting that he can switch their positions with just a few swipes. It seems impossible, but Lenny has long, crazy fingers and he's quick and he talks nonstop. Distracted by all the patter, you don't realize that he is able to hide multiple letters under his fingertips. This allows him to transfer 2, 3, or 4 letters at a time from one word to the other.
We took some covert video and played it back in slow motion. Watch carefully:
TESTS RAINING | . | | . | | I,N,G | | . | v . v TESTINGS RAIN | . | | . | | T,E,T,G | | . | v . v SINS TREATING | . | | . | | T,A,T,G | | . | v . v TASTINGS REIN | . | | . | | T,A,S | | . | v . v STING RETAINS | . | | . | | R,E,I,S | | . | v . v RESISTING TAN | . | | . | | S,T,I,G | | . | v . v RESIN STATING | . | | . | | T,A,T,G | | . | v . v RESTATING SIN | . | | . | | R,E | | . | v . v STATING RESIN | . | | . | | S,T,I,G | | . | v . v TAN RESISTING | . | | . | | R,E,I,S | | . | v . v RETAINS STING | . | | . | | T,A,S | | . | v . v REIN TASTINGS | . | | . | | T,A,T,G | | . | v . v TREATING SINS | . | | . | | T,E,T,G | | . | v . v RAIN TESTINGS | . | | . | | I,N,G | | . | v . v RAINING TESTS
1. At each step, Lenny transfers 2, 3, or 4 letters from one word to the other. Each side remains a valid English word after extraction and insertion of the letters.
2. The letters can be extracted from anywhere in the word, and they can be inserted anywhere in the other word. They need not be contiguous.
3. The spacing of the letters does not need to be maintained since Lenny can easily adjust the spacing of his fingers. However, the ordering of letters must be maintained because Lenny can't change the ordering of his fingers.
4. The direction of movement does not need to alternate between right to left and left to right. At each step, Lenny can swipe in either direction. (See the eighth and ninth step above, for example.)
Now that you know how it's done, see if you can figure out his latest scam:
BTW, as long as it doesn't involve money, Lenny is a pretty easy-going guy. He doesn't care about American and British spellings (THEATER or THEATRE) and allows words like HEARTED with old and new meanings.
Here is an even more lowbrow solution than the ones found by @GarethMcCaughan: