Evolution!

Today I decided what the next stage of human evolution should be. Visible Farts.
This may sound a little purile at first but has numerous applications. Firstly those dirty sods who release noxious gasses in small spaces. A mere smell can be ignored and most don't remark when they come accross a nasty niff with an obvious guilty party. The civilised person won't start shouting about how filthy and rotten it is. However that guilty party may feel a slightly greater urge to self regulate if they know that inapropriate release will cause them the embarrasment of standing in a purple cloud for five minutes.
True, this may make some public conveniences impassable but that wouldn't be much worse than what we suffer right now.
You might think I'm being a bit negative about the humble fart. Not very British of me. however there is also a huge potential for comedy with regards to visible farts. Maybe if different colours represented different strengths, ie. Green smoke = bit humid - slightly mucky and red = this is the fog - you will be turned inside out.
It can easily be faked for the purposes of showing panic on stage and screen.
(screen notes
ripley : "The alien's here somewhere.."
slight tense pause,
Cue : Alien crashes through the ceiling - Cue : Delicate orange mist)
Well I reckon it's an idea with legs, let's hope it runs...or maybe not "runs"...nasty.