Paste this code on you're site:
<iframe src="https://wavespaceplaza.neocities.org/" width="100%" height="500" style="border-style:solid; border-width:20px 1px 1px 1px; border-color:lightgrey"></iframe>
Here it is in action:
You may want to adjust the "height" paremeter to your liking.
Note that if you're site has background music, it won't automatically stop when the wavespace music plays
If you like this webapp, you can check out all my stuff on My Main Website