Deponia

In the Post Office, armed with the tranquilizer and espresso in your inventory, you need to solve this trophy puzzle before you proceed with radio communicating with Cletus. The way the postage system works is that stamps denote the urgency of the delivery, or how fragile it is. To radio Cletus, you need to utilize the actual system atop the post office (not the operator's platform). But the Mail Clerk will not leave his post without a distraction.

To activate this trophy, open the two hatches on the right side of the map. In them, you will see two cats, one white and one orange. The one on the left operates the speed of the package delivery system, while the right operates the postage. We need to make it so there is no postage on what we're trying to get ordered, which happens to be vouchers from Toni's Shop.

(Long story short: Tranquilizer from the Emergency Station + Funnel from Assembly Hall + Dart from the Alley Bar = blow pipe. Use this in the window to Toni's Shop to tranquilize her temporarily, then enter to get vouchers.)

Use espresso on the orange cat (delivery, on the left) and then tranquilizer on the white cat (postage, on the right). Hand a voucher to the mail cleck, who will procure the package and send it through the system. The package will make it through well before the tranquilized cat has a chance to lick a postage stamp on it, making the robot burn the package without postage on it.

Once you obtain this trophy, return the cats to their proper state (reverse their state by giving them the opposite item) and then repeat the condition: give the espresso to the white cat (postage) and the tranquilizer to the orange cat (delivery). The package will be overstamped, requiring insane amounts of bubble wrapping to protect it (thus providing you with the post office solution too).