Building an Engine, Part 5

---Today's Brick---
Name: Technic pin
Size: 1 diameter, 2 or 3 long
Color(s): Black
This is what I use for holding our little Technic engine together.
Such a simple looking piece, and yet this is the most essential Technic piece Lego makes. These two types of pins are used to connect all kinds of Technic pieces to one another, making all kinds of different Lego models.
This is a simple structure I built using the four pins in the first picture. Notice that the 3 long pin can be used in two different ways: with equal lengths on each side of the beam, as on the yellow piece, or with most of its length on one side of the beam, as on the red piece. Tomorrow: the complete engine.