I want to make a surprise for my girlfriend. When she comes home from work I will get her involved in a love game that I invented the other day. I will buy 8 balloons and into each balloon I'll place a little piece of paper with a letter. All the letters collected together will combine the phrase "I love you". In addition to it every balloon will have encrypted instructions on the location of the next one. And the last balloon will have a key to my bedroom inside of it. To every balloon I will tie a pin so she could easily "open" it by pricking.

Then I'll hide the balloons somewhere in secret parts of my apartment and invite my girlfriend. When she's about to come I'll leave the door unlocked and put a note on it that the door is open. The first balloon will be right on her way. She will see something inside it and a pin hanging next to the balloon. My girl is very smart; she'll guess what should be done. And she will prick the first balloon and take the piece of paper hidden