Customising the initial state of 'Universe'

Here's an example. To start the Universe simulation in its 'default' initial state, try the following web address:

To start it in a customised initial state, we add extra information to the web address. For example, the initial horizontal velocity is a variable called v_xv, and its 'default' value is zero. To give the planet a non-zero initial horizontal velocity, try:

Complete list of variables for 'Universe'