Q. Re- Question 2259 - Playing Scrabble on Shabbos; Can one place a message for his family or guests on a table by using Scrabble letters not attached to anything, but covered with a heavy glass utensil, such as a transparent rectangular pyrex container or similar, so the kids won't grab or move the letters? The covering glass is not touching the letters, just protecting them.
A. As mentioned in question 2259; Poskim permit placing letters together on a board or similar and form words, when the letters are not fixed or attached to the board, or to each other, or when not being held together by a surrounding frame. (Shemiras Shabbos K’ 16: 23, Piskei Teshuvos 34: 16, quoting Igros Moshe O.H. 1:135 and Chaye Adam 37:6).
Horav Shlomo Miller's Shlit'a opinion is that although in principle it is permitted, it is preferable to avoid when not in need.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit'a