From "Try To Remember!"

By Frank Herbert

"The ship had flapped out of a gun-metal sky over Oregon, its shape that of a hideously magnified paramecium with the edges that rippled like a mythological flying carpet. Its five greenskinned froglike occupants had delivered the ultimatum, one copy printed on velvety paper to each major government, each copy couched faultlessly in the appropriate native tongue: 'You are requested to assemble your most gifted experts in human communication. We are about to submit a problem. We will open five identical rooms of our vessel to you. One of us will be available in each room. Your problem: To communicate with us. If you suceed, your rewards will be great. If you fail, that will result in destruction for all sentient life on your planet". 1961.