Here’s my postcard for water! I did this over 30 minutes while hand washing clothes in the tub (probably lasted a little too long because I got carried away and forgot I was soaking the clothes, but oh well). Each line is an interval of 30 seconds. The silver lines represents clean water and the black lines show when the water turns dark because of the blue dye. The length of the lines also represent the amount of water in the tub at any given point in time, and the little blue circles are the number of bubbles present.