Time-stopped snowflakes in Boom, just like in Twice Upon A Time. My literal first thought when I saw them was "Testament?"

Susan Twist in Church on Ruby Road asking Ruby's band to play Gaudete, a Scandinavian carol according to Wikipedia. (Dårlig Ulv Stranden, anyone?)

Today is the 3rd Sunday of Advent, also known as Gaudete or “Joy” Sunday!

1 Oh, come, Oh, come, Emmanuel,

And ransom captive Israel

That mourns in lonely exile here

Until the Son of God appear.

Rejoice! Rejoice! Emmanuel

Shall come to thee, O Israel.

2 Oh, come, Thou Rod of Jesse, free

Thine own from Satan's tyranny;

From depths of hell Thy people save

And give them vict'ry o'er the grave.

Rejoice! Rejoice! Emmanuel

Shall come to thee, O Israel.

3 Oh, come, Thou Day-spring from on high,

And cheer us by Thy drawing night;

Disperse the gloomy clouds of night

And death's dark shadows put to flight.

Rejoice! Rejoice! Emmanuel