Years ago a saw a "shtender" (it's a small portable "riser" commonly used to prop the prayer book up while praying in shul. It has other uses, also.) that is constructed by sliding a piece of wood into two grooves built into each of the two sides of a larger piece of wood.
To get some sense of what this looks like, begin with this idea, lower right picture on the page. However, instead of a hinge connecting the top and the bottom, imagine that the top part, where the book rests, has 2 narrow strips of wood on its underside. the box part (bottom of the stand) has two grooves on the top of the box. To construct the shtender, you slide the top piece into the groves of the bottom piece. Similar, in a sense to some wooden crates that have a slide-on lid.
Can this shtender be made on Shabbat? Is this a problem of the prohibition of "boneh" - (construction / building)?