A while ago the company I was working for were approached by Lego to develop some cross-promotional software stuff. They gave us Lego Darth Vaders, and a "brandbook", which outlined on pain of torture what we could and couldn't do with the Lego IP. Some interesting things were :

Lego tried to redesign their logo. There is an excellent page in the booklet where they show the familiar 1970's logo followed by a series of proposed logos, ending in the 1998 accepted one. Each logo is less and less "daring" than the last, until finally they settled on one which is almost inperceptably different from the starting point.

You cannot print the Lego logo in monochrome, or superimpose anything onto it. It must always appear on any item which makes any visual reference to the lego components. The word Lego must always be in all caps.

Children in promotional literature must be shown in groups with adults nearby.

Legomen have guns and swords but cannot be shown using them. There is no violence or emnity in the Lego universe.

If legomen are to be portrayed as animate, they are to have fluid movement rather than the limited single-axis movement of the real figures.

Lego does not designate a target gender for any product (this was cleverly juxtaposed with the ultra-macho Lego Rock Raiders and the ultra-girly Legotown).

Don't draw the legomen looking stupid or having sex with livestock or we'll fucking kill you. With real guns.