We do love a bit of internet archaeology here at the Junkyard, and this little snippet of news has 'digital Lara Croft' written all over it. Reddit user u/LeFaggo recently posted the image above to the r/Dreamcast thread, along with a link to the original source - the Japanese Patent Office.
Could this be a hitherto unknown prototype of the Dreamcast swirl we all know and love? The discussion in the thread points out that this mysterious trademark was actually filed after the familiar Dreamcast swirl that made its way onto the final console design; but it is also noted that sometimes trademarks are filed weeks or months after their creation just to keep them in the system, so to speak.
Either way, it is an interesting glimpse at what could have been. Rather surprisingly, this image doesn't appear anywhere in the excellent Sega Dreamcast: Collected Works by Read-Only Memories. Surprising because the authors had full access to Sega's own internal archive; and the book features many concept images for the Dreamcast's shell design. Perhaps this prototype trademark was filed way back in 1998 and simply forgotten about, hidden in plain sight for over 20 years.
Thanks go to Rich from Dreamcast Years, who then alerted my my colleague Andrew Dickinson to this, who in turn WhatsApped me while I was trying to light a bonfire. Oh, and thanks of course to the ever alert r/Dreamcast community for another excellent and intriguing discovery.