Constellation Lyra

Vega, the brightest star in the Summer Triangle, belongs to the constellation Lyra. It's the brightest star in the constellation. At magnitude 0, it's also the fifth brightest star in the sky.

Hanging off Vega are two pairs of stars. Two of them, the brighter of the pairs, are named Sheliak and Sulafet. The four stars form a parallelogram, as shown in the chart above.

Note another star labeled the Double Double. If your eyes are sharp enough, this star appears as a double star. These stars are doubles themselves, making the Double Double a quadruple star system. A sharp telescope on a good night will show all four stars.

References:

The 10 Brightest Stars
Constellation Lyra