Changes made to make it compiled in ejs 4.2.

From "Spring-Mass System for [color=red]'[/color]A[color=red]'[/color] level Physics, Oscillations, Damping, Resonance by weelookang@gmail.com homepage: http://lookang.co.nr"
to "Spring-Mass System for -A level Physics, Oscillations, Damping, Resonance by weelookang@gmail.com homepage: http://lookang.co.nr"

strangely a disabled page is also causing compiling issues.
the code is _pause()
seems to be not recognized in ejs 4.2