Others have summarised lemmy, lemmy.world and its use quite well already, so i just looked for the connection to perchance:
I checked perchance.org and they mention that they have a community on lemmy where one can ask for help or share creations. (Similar to the "No Stupid Questions" community you posted this to)
So no real relationship other than that they use Lemmy as a platform for their users to exchange on and use lemmy.world as a "provider" for their community space (or "forum" in older words)
Others have summarised lemmy, lemmy.world and its use quite well already, so i just looked for the connection to perchance:
I checked perchance.org and they mention that they have a community on lemmy where one can ask for help or share creations. (Similar to the "No Stupid Questions" community you posted this to)
They specifically link to this community: !perchance@lemmy.world (https://lemmy.world/c/perchance)
So no real relationship other than that they use Lemmy as a platform for their users to exchange on and use lemmy.world as a "provider" for their community space (or "forum" in older words)