Four strand braid.
A simple way to braid with four strands.

Arrange your strings like this. And decide where the middle will come. Take the leftmost string and let it jump over the string on its right, to the 'middle' Take the outmost string on the right and let it jump over two strings, towards the middle. From here on you just repeat, left string to the middle.
And right to the middle. You can keep on going this way forever. You can also braid from the middle to the sides but I think this is the easier way.
 
Back to start. one step backwards.
©Willeke 2005