Our sewing instructor was having a fashio show and all her students were invited to show off their creations. Simon really wanted to have another item from the "tissus extensibles" class, so he made the 2 items in 1 day!
Simon used 2 patterns to create his long johns: Jalie's 2327 and 2918

He extended the boxers to make his legs, accounting for the width of his thighs, knees and ankles. His shirt he made a -5 to make it tighter and he made a mock turtleneck.The length is a bit longer so that when he moves around the shirt does not lift past the pants. I think he will be nice and warm in these. Coupled with the sweater he made from the same pattern and the winter jacket he made, he is good to -40 Celsius!