The UNIX or Linux tee application does what its name suggests if you're familiar with various plumbing connectors—it splits its input into two different streams.
Anyone who has patted a dog, stroked a cat, sat under a tree with a pint of beer, given or received a bunch of flowers or chosen to walk through the park on a nice day, understands that.
And to make all men see what is the fellowship of the mystery, which from the beginning of the world hath been hid in God, who created all things by Jesus Christ.