It shows the four candles for the four Sundays before Christmas. While looking for inspiration for this illustration I found several Advent wreaths with three purple candles (Did you know that purple opposite to violet is a non-spectral colour together with grey?) and one in pink. Becoming curious whether there is a purpose behind this colour scheme, I deciced to look it up in Wikipedia. And there actually is no topic you cannot learn anything new about. In this case I found out that the lithurgic colour for the time of Advent is purple. As the third Sunday is called 'Gaudete' (rejoice) the candle for this day is pink, considered to be a happier shade of purple.
For me one of the best things in illustration (apart from inventing and drawing) is looking up on issues and discovering so many interesting news even about the most ordinary topics.
Have a wonderful Christmas time!