Sesame Street is 45 years old today, and the warm-spirited puppeteers behind the show's Twitter account did a fun thing. They shared 45 facts about Sesame Street over the course of the day. Chief among them is the fact that Oscar the Grouch was actually orange for the entire first season of the show. Orange!

The story behind the change is pretty simple: Jim Henson decided that Oscar should be green. The show did offer a fun explanation about the color change. Apparently, Oscar went on vacation to Swamp Mushy Muddy and came back green.

That's not the whole story, though. Originally, Oscar the Grouch wasn't supposed to be orange or green. He was supposed to be magenta. Here's a design sketch from 1969:

The reason why the world never saw a magenta Oscar, however, is a technical one. At the time, color TVs were relatively rudimentary and couldn't handle the color magenta very well. So Oscar became an orange grouch instead.

It's also worth pointing out that the puppeteer in charge of Oscar was none other than Carroll Spinney, the man who was also Big Bird for nearly four decades. Spinney says that Oscar's rough voice was actually modeled after a cranky New York City cab driver. The first puppet Spinney used wasn't quite right, either. It lacked foam and required the puppeteer to use his left hand, awkwardly. (Spinney was right handed.) Part-way through the season, Sesame Street added foam and an eyebrow mechanism to the Oscar puppet and also changed around the set so that Spinney could use his right hand.

From mid-1970 until today, Oscar the Grouch hasn't changed too too much. His fur became a little less wild and his eyes moved around a little bit. But in all those years, Oscar never lost that lack of charm.

A few more highlights from Sesame Street's birthday fact-fest: