Question
Some Poskim rule Marit Ayin is an issur d’oraita, according to this view are noahides or ger toshavs prohibited from Marit ayin in mitzvoth they are commanded regarding

Question
Does a voluntary prayer ever become a mandatory one? For the past several years, I’ve been praying to G-d in my own words in English for something I have wanted very much. G-d has still not answered my prayers. I have lost nearly all hope that G-d will grant my wishes or that what I am praying for is meant to be. I still fully believe in G-d, though I have come to the conclusion G-d has not intended for my wish to come true. At first my prayers were heartfelt, but now I am just rushing through it as part of my daily routine that I say in identical, memorized words each day. I am tired of taking the time out of my day to recite this prayer and I feel like quitting. But I am afraid if I quit, I am going down the ladder.

Question
Is it permitted to walk on a non-electric treadmill on Shabbat that is just a belt that uses gravity and has no electric components and does not measure anything?