We prove a number of results related to a problem of Po-Shen Loh [7], which is equivalent to a problem in Ramsey theory. Let a = (a 1 , a 2 , a 3 ) and b = (b 1 , b 2 , b 3 ) be two triples of integers. Define a to be 2-less than b if a i < b i for at least two values of i, and define a sequence a 1 , . . . , a m of triples to be 2-increasing if a r is 2-less than a s whenever r < s. Loh asks how long a 2increasing sequence can be if all the triples take values in {1, 2, . . . , n}, and gives a log * improvement over the trivial upper bound of n 2 by using the triangle removal lemma. In the other direction, a simple construction gives a lower bound of n 3/2 . We look at this problem and a collection of generalizations, improving some of the known bounds, pointing out connections to other well known problems in extremal combinatorics, and asking a number of further questions.