The Nobel Prize invitation

The year is 1886. Rita Levi-Montalcini is about to receive, with Stanley Cohen, the Nobel Prize in Physiology for her discovery of the nerve growth factor. What a joy to see her work and research rewarded.

The award ceremony is tonight. Rita has just finished writing her speech and getting ready. She heads to her office to pick up the invitation but cannot find it. She finds a letter on the table and realises that a jealous scientist has stolen the invitation. Without it, Rita Levi-Montalcini will not be able to attend the award ceremony!

The invitation is hidden in a safe and she only has 45 minutes to find the combination.

Help Rita crack the 4-digit mechanism in the safe with the clues left in her office.