how to make a block where i can place it in a 1 block area, and have multiple of them in that same block, like legos

Just not realistically possible, unless you wanted to create a block with every single possibility of where a lego would be placed on it as a blockstate, like 256x256x256 blockstates or so, if you have bigger legos then I guess it's viable with like 16-64 blockstates maybe

An 8x8x16 block? Either way you would need to make all the blockstates possible, breaking each one individually would not really be possible, you could right click pick them back up, you can use px py pz to get exact click position to set which blockstate to set to

It will be quite complex icl… but definitely doable if you only need 4 blockstates, depends how it’s done