Tricky Simple Project

OK,
Reference several earlier posts and it should become evident that from time to time I build pieces for our house. Usually these things go fairly well...I am no carpenter but I usually get by with a string and a prayer.
Tonight I started what should be a reasonably easy project - planters for LC to use on the porch during the fall and winter (as her clay pots will freeze and break). Well, in an all too predictable outcome - the simple project is going to be difficult. I just came up from the basement after making some angle cuts and - suffice it to say - I grabbed a Rolling Rock out of the cooler on the way to the stairs....