If you’ve ever wanted a knot to impress, here it is! Trinity knot is one of the necktie knots that gained popularity recently. Its three way triangular shape which makes it very impressive. Once you mastered the technique, trinity knot is quite easy to tie.
It is suggested to use a tie that is either patterned or has small stripes, like the tie pictured. Do not use a tie with several different colored stripes, as the stripes and colors will collide in the knot.
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Source here, here is the video tutorial if you wanna follow the instructions directly.