In 12-hour striking, used most commonly in striking clocks today, the clock strikes once at one a.m., twice at two a.m., continuing in this way up to twelve times at 12 noon, then starts again, striking once at one p.m., twice at two p.m., up to twelve times at 12 midnight.
The half-life of clonazepam (Klonopin) is about 30 hours. If you only take one dose, the general rule is the medication will statistically be out of your system after 5 half-lives, when only 3.125% of the drug remains in the body. This would mean that clonazepam will be out of your system after about 150 hours, but this can change based on your specific enzymes.
If you took the pill from someone who is prescribed Neurontin, you need to understand that that person has likely already been started on a lower dose of the drug and worked up to the higher dose. That said, Neurontin has an elimination half-life of 5-7 hours, if you have healthy kidneys. That means that half of the drug will be gone from your system in 7 hours, 75% gone in 14 hours, 87.5% gone in 21 hours, etc. As far as I know, commercial drug tests do not routinely screen for Neurontin and I don't believe there is any cross-reactivity with controlled substances.