I started with some water and flour and some grapes from a neighbor's yard (no yeast added!):
And now I have this:
Using a Wild Fermentation recipe, I made a starter (actually, two: I doubted the first but it has since come into its own). The first starter got foamy and yeasty so I strained the grapes (the white on grapes being naturally-occurring yeasts) and then it went dormant. I started another. I waited. I almost wondered if they had gone off as they taste(d) sour. I'm guessing that's the sour in sourdough. Then I transferred both to an open window on those warm days of last week -- and voilà! -- now I have two active starters. Sour and yeasty like a sponge for a dough. Hopefully tomorrow I'll see how they stand up to dough, rising and baking.