Lego on Shabbos
Is a child permitted to play with Lego on shabbos?
Playing with lego is permitted on Shabbos. The pieces connect in what is considered a weak connection, specifically designed to easily come apart, and rebuild. Even specific figures that are built from a lego set are generally taken apart soon after their building and rebuilt differently or even the same way.
One who intends to build a lego model in order to keep it as is for a long period of time and specifically not take it apart, should refrain from doing so on Shabbos.