The Mishna in Shabbos (daf 73) teaches us that there are 39 Melachos, 39 types of creative activities which are forbidden on Shabbos.  And, the Mishna tells us, these 39 melachos are the activities that were used in the creation and later the use of the mishkan.   We know that each melacha tends to have a shiur, a certain amount of the activity that is meaningful enough for one to be liable.  For example, when it comes to the melacha of writing, it’s writing 2 letters.   So, the Mishna asks,…