Framework is changing the shape of the power button on its open source, 3D-printed cases for its mainboards after it received a letter from Lenovo's legal team suggesting the button looks too much like Lenovo's Legion "O" trademark, Framework tweeted today.

The clip of the letter can be seen in the tweet below, which you may have to expand.

The @Lenovo legal team says we have to change the power button on our 3D printed case, so we’re opening up a Community contest! Whoever can come up with the best new power button design gets a free i5-1135G7 Mainboard.

The letter, directed to Framework Computer CEO Nirav Patel, is only shown in a partial screenshot and is on letterhead from Lenovo's lawyers at Taft Stettinius & Hollister LLP. "We believe that the Broken O Case" may infringe Lenovo's trademark rights in the LEGION Trademarks, and may ultimately lead to consumer confusion," it reads in part, further suggesting that Framework's case or mainboard may appear to be affiliated with Lenovo. While we can't see the rest of the letter's contents, it may be a cease and desist letter.

Framework doesn't seem interested in fighting the challenge. Instead, it's starting a community contest for the new design. Entries must be submitted by 11:59 Pacific Time on Aug. 25, with a winner "judged subjectively by our CEO"  on Aug. 26.

No date is shown on the snippet of the letter that Framework tweeted, so it's unclear when Lenovo's lawyers sent it. Framework first started offering the 3D printing schematics in April when it began selling mainboards separately from its computers. It doesn't appear that Framework ever directly sold the case in its marketplace.

Lenovo did not respond to a request for comment in time for publication. We'll update this story if it responds. Framework acknowledged a request but didn't return with a statement in time for publication.

Lenovo's Legion lineup consists of the company's premium gaming laptops, desktops and monitors. Some lower-end laptops are also under Lenovo's Ideapad branding. Lenovo's "O" design is typically used within the word "Legion" on its products, though previous versions of the design were used alone. Framework doesn't currently offer any products other than its Framework Laptop and components for it and has yet to step into gaming.

The "O" shaped power button on the 3D case isn't on the Framework Laptop, so its flagship product should be unaffected.