Cliff landscape generator

[Sylvain Sauvage]

Thanks!

I just uploaded a new version:

• it corrects a few glitches with paths,
  
• it allows multicoloured rocks / strata (enter a list of colours “L,M,N” to have three equal strata; you may add weights to make some strata thicker, “L,M:2,N:3” means L is used 1/6th of the height, M 1/3rd and N half the height).