like this, although this doesn't work inside a textarea
<span ng-if="$index === 0">Tap to start writing. Swipe left when you have a new, related idea.</span>
<span ng-if="$index === 1">Explore your related idea here, then swipe back. Or, swipe left again to explore another new, related idea.</span>
<span ng-if="$index === 2">These will change color to let you know how deep you've gone.</span>
like this, although this doesn't work inside a textarea