Not much good comes from taking expired medicine, but it's not always obvious when the drugs in your cabinet are too far gone to safely ingest. To remedy the situation, Kanupriya Goel and Gautam Goel devised concept packaging that's basically impossible to misinterpret. It's called Self Expiring for exactly the reason you'd suspect: the packaging gradually "expires" over time, ultimately displaying a "not fit for consumption" message when there's no going back and it's time to trash your meds.
As for how the system works, it involves three layers. Two of them — one a traditional medicine label, and the other the expiration warning — are separated by sheets of diffusible material. The ink contained in the expiry message seeps through over time, starting when the medication is first packaged. The Goels hope this will "prevent retailers from illegally selling expired medications for personal gains." The simple, yet ingenious concept has earned its creators a Red Dot award for design, though it's difficult to say when (if ever) you'll be seeing the Self Expiring packages at your local pharmacy.