The objective is to use walkie-talkies (or mobile phone, etc.) as the only means of communication to describe how to build an exact copy of a set of Lego models.
2 Walkie-talkies (or mobile phones)
Create two identical sets of 3 or 4 simple Lego models. Once created, keep one set complete and break the other set into individual parts, mixing all the bits together in one bag.
Split the patrol into two, one will be the communicators and the other the constructors.
Put the two teams in separate rooms where they cannot see each other, the communicators with the complete models and the constructors with the bag of bits.
Give each team a walkie-talkie (or similar). Using the walkie-talkies, the communicators have 15 minutes to describe each of the models they have in front of them to the constructors.
Based on the instructions from the communicator, the constructors have to try and build exact copies of the models.