I'll be observing you'll be observing he'll be observing we'll be observing you'll be observing they'll be observing
Future perfect
I'll have observed you'll have observed he'll have observed we'll have observed you'll have observed they'll have observed
Future perfect continuous
I'll have been observing you'll have been observing he'll have been observing we'll have been observing you'll have been observing they'll have been observing
I'd be observing you'd be observing he'd be observing we'd be observing you'd be observing they'd be observing
Past
I'd have observed you'd have observed he'd have observed we'd have observed you'd have observed they'd have observed
Past continuous
I'd have been observing you'd have been observing he'd have been observing we'd have been observing you'd have been observing they'd have been observing