Brick 1×1 with studs on four sides (Travis brick)
This brick is incredibly useful, and has become many builder's favourite part. In the space community it is nicknamed The Travis after talented builder Travis Kunce. He liked the part so much he decided to make a tattoo of it on his back. Travis has since passed away, but his builds - and tattoo - are still available on Brickshelf.
To find the different pieces needed for this technique you can search LEGO's online Pick-a-Brick for the design ID's. We link other market places directly on each individual piece page, which you can find below.