Spacing Out Exposures (Article ID 82)
Abstract: When a player exposes tiles on the flat part of their rack, it isn’t required, nor is it a rule that they separate them with spaces. However, it is recommended as a courtesy to allow spaces between your exposures, especially when Jokers are involved.
Question from a player: When a player calls for two or three exposures, are the tiles to be placed together or separated by a small space?
Answer from the NMJL: “When a player has multiple exposures on the rack, it is courteous to leave a space between the exposures.”
Source: Mah Jongg Made Easy 2020 page 14
Other answers from the NMJL:
“There is no absolute ruling about how to place the exposed tiles on your rack; however, it certainly would seem to be courteous to put a space in between exposures, especially when there are jokers involved.”
“A player is not required to place exposures in the order in which they are shown on the card; however, when mah jongg is declared, tiles should be re-arranged to show the correct order. When a player has multiple exposures on the rack, it is courteous to leave a space between the exposures”
Sources for other answers: National Mah Jongg League Bulletin Q&A (2017, 2020 page 14) https://www.nationalmahjonggleague.org