This one is pretty self explanatory. Get your lego. Get your kids. Combine the two and give them an instruction:
Build a tree.
My kids are young – almost 4 and almost 2. So they used Duplo and needed a bit of direction. But the 4 year old understood completely.
Build a Lego Christmas tree … it could end up looking like a giant mound of green blocks. Or a star. Or whatever.
Let your kids create whatever they want and then revel in it’s awesomeness.