Continuing with the blobbing theme PBers. These are water puddles with color dropped in plus tilting the paper to get the color to run around and 'mingle'.
I learned to mingle colors and make blobs from watercolor artist David Dewey.
And from his book, The Watercolor Book.
Here's a good exercise anyone can do if they have a few art postcards. Piero Della Francesco used a wonderfully harmonious color palette and you'll understand it better when you try to match the colors.
Some color blob thumbnails jammed on a page.
Several Tuscan blob buildings plus color swatches.
Multiply color swatches with a landscape plopped in the middle.
A color wash ground with a little Tuscan landscape laid on top.
There were plenty of color wash pages in my old sketchbook. These are 'color beginnings' as J.M.W.Turner called them - a big atmospheric wash of colors.
Why not paint a Paris skyline on top with a little help from Google images?
After mixing up (but not well-mixed) a biggish puddle of cobalt blue + French Ultramarine blue + Burnt Sienna + Burn Umber, I begin drawing the Arc de Triomphe with a brush loaded with unmixed 'organic color'.
Extending the puddle of 'mingled' paint down and across, always keeping it wet and working fast I add the Eiffel Tower...
Ever onward, tilting the paper a bit to help the wet paint/colors run and mingle across the page.
Now YOU do it!