Triangle shaped object moving steadily across sky

The object consisted of three triangle shaped lights steadily moving in formation toward the east. There were two blinking points of light in the back and one solid light in the front creating the three points of a triangle. The blinking lights looked like airplane lights but the solid light in front was inconsistent with this. It moved steadily across the sky about the same speed as a high flying airplane would. However, if the lights were all one unit it was either incredibly masive or flying incredibly low without generating any sound. If it was not one unit, it could be two planes flying in tandem but I can't think of an explanation for the solid front center light. The lights were mostly blinking alternately although briefly they were in sync. I watched them till they dissapeared behind a building to the east. The blinking lights were similar in color to plane lights. The solid light in front was white or yellow.