The video of my project working can be found here. My board works as follows. If I press the first switch, I do not know a priori if the lights will turn on. If I press the second and the first together, the lights will turn on with 100% probability. To randomly turn on the light when the switch is activated, I create two random numbers. The Arduino documentation doesn’t say how its random numbers are distributed, but I assume that they are uniformly distributed between the min and max arguments to the random function. With the two random numbers in hand, I perform a test to see if the first is larger than the second. If it is, then the lights will turn on if the switch is activated. If not, then the lights won’t turn on. The code for my loop() function can be seen here.