I'm not starting the triphasic yet today. I'll start in a few days, and considered to the last moment starting today, but in the end I feel a bit sleep-deprived at the moment. I've been sleeping a little erratically lately and triphasic sleep doesn't take kindly to sleep deprivation.
So, triphasic sleep can be of varying patterns, but I'm going to use the simple three times 1½ hours program. According to the limited info available, it's relatively easy to adapt, but as you know, my track record isn't the most solid.
Tonight I'll have a full night's sleep and then consider starting tomorrow. It depends on how I feel, but you can expect this experiment starting soon.
I'm lacking concentration at the moment so I'll get back to you later more.