My ds is nearly 13 months and has a pots for stacking (10 of them and they stack up to taller than him).
He started walking a few weeks ago but he was really steady on his feet for ages before that. For at least the past 2 months he's been able to stack them all up and then he neatly stacks them back into each other again (no knocking down the tower, he likes things neat and tidy!)
He's generally quite keen on stacking and organising things - he will break into cupboards to put things away.
Now his dad and I are extremely messy and disorganised so is this just a random trait, is he advanced, weird or just going through a phase??