Various Melachos
9. Several types of games involve multiple melachos or Shabbos issurim. We will first list different types of melachos and issurim that one can end up violating, then we will give some examples of games.
10. Borer. When there are items one is interested in mixed together with items he is not interested in, he must take the ones he wants from the ones he doesn’t [אוכל מפסולת], not the other way around. Also, the purpose of separating them must be for immediate use [לאלתר], not for later, and he must use his hand [ביד], not a utensil (שו''ע סי' שי''ט ס''א ).
11. Noisemaking [השמעת קול]. One may not intentionally use an item to produce a noise on Shabbos out of concern he might fix a musical instrument. This is an issur d’rabanan (שו''ע סי' של''ח ס''א ).
12. Leveling the ground [אשוויי גומות]. One may not sweep the ground with a broom on Shabbos due to the issur of leveling the ground (שו''ע סי' של''ז ס''ב ). One may not do anything on the ground which requires the ground to be level due to this concern (שו''ע של''ח ס''ה ).
13. Kesiva. Some poskim hold one may not tightly connect letters made from a material together on a surface or background, as that is like writing (מג''א סי' ש''מ סק''י ). Some allow it, as it is not the action of writing (נשמת אדם כלל ל''ז סק''ב ). Similarly, the poskim discuss whether putting together different letter parts is an issur of writing (שו''ת רמ''א סיק קי''ט, ט''ז סי' ש''מ ק''ב ).
14. Binyan with utensils [בנין בכלים ]. Although there is a rule that binyan and stira do not apply to utensils or objects (גמ' שבת דף ק''ב ע''ב ), the poskim hold that when parts of an item are connected by strongly sticking one into the other, there is an issur d’oraisa of binyan with utensils (שו''ע סי' שי''ד ס''א ). If two things are attached tightly without inserting one into the other, it is an issur d’rabanan. If they are only loosely connected, it is mutar.
15. Makeh b’patish. One may not make a utensil or complete the final stage of a utensil on Shabbos even if there is no issue of binyan with utensils, e.g., it is done loosely, due to the issur of makeh b’patish or tikun mana.
16. Making an ohel. One who makes a proper, lasting ohel is chayav a chatas (שו''ע סי' שט''ו ס''א ). The minimum size of an ohel is a tefach high with an area of a tefach by a tefach (תוס' שבת קל''ח : ד''ה שאין ). It is an issur d’rabanan to make a makeshift ohel for protection or for usage of the space underneath even if there are no walls (שו''ע שם ).
17. Business [משא ומתן ]. It is an issur d’rabanan of business for one person to sell, buy, or transfer ownership of an item to another person on Shabbos.
18. Weekday activities [עובדין דחול]. There are some things which, strictly speaking, may be done on Shabbos, but were forbidden by the poskim because they are weekday activities, e.g., riding a bike on the street where there is an eiruv and the like.
