Unreal Engine

This is a screenshot from inside Unreal Engine 4. The box in the middle are the "blueprints" for my character in the game, essentially its code to make it do things.

This is an example of a node which is like a little block of code, this red node means that whatever is inside triggers an event in the game. In this case it means when the "T" key is pressed and released during my game an event will happen.

This blue node is an example of a function. It will make it so that event is attached to it using the pins, it will print out a string which says "Say Hello To My Little Friend". 

This is what the nodes look like when they are linked up by the pins. These nodes make it so that when the "T" key is pressed in my game it will print a string onto the screen, and when the key is released it will print another. 

All nodes are connected by exec pins which look like this.