Microsoft’s engineers and executives spent two years creating a new line of smartphones with playful names that sounded like creatures straight out of “The Cat in the Hat”  Kin One and Kin Two. Stylish designs, an emphasis on flashy social-networking features and an all-out marketing blitz were meant to prove that Microsoft could build the right product at the right time for the finickiest customers  gossiping youngsters with gadget skills.

But last week, less than two months after the Kins arrived in stores, Microsoft said it would kill the products.

“That’s a record-breaking quick end to a product, as far as I am concerned,” said Michael Cronan, a designer who helped drive the branding of products like Kindle for Amazon and TiVo. “It did seem like a big mistake on their part.”

The Kins’ flop adds to a long list of products  from watches to music players  that have plagued Microsoft’s consumer division, while its business group has suffered as well through less-than-successful offerings like Windows Vista and Windows for tablet computers.