Triangulum

6 Trianguli is actually a quadruple physical system as each of the stars visible above has a close companion.
X (Chi) Trianguli (J 3257) at first glance appears to be a binary pair but is actually a triple star. It has a third unseen stellar companion (B) that orbits around X Tri with a period of 0.95 days . Its orbit is such that it passes in front of the main star blocking a portion of the light that reaches our eyes causing a 2 magnitude dimming of the main star. – from Magnitude ~9.0 down to magnitude ~11.0 and back up again over a four hour period.