Amazon (AMZN +1.8%) is working on two smartphones - one of which has a 3D screen - and a music-streaming device, the WSJ reports. The 3D phone is said to feature eye-tracking tech that makes images "seem to float above the screen like a hologram," and might also allow users to "navigate through content using just their eyes." Sources cautioned there's no guarantee the devices, as well as an Amazon set-top (previous), will ever be sold. LG and others have experimented with 3D phones, but the devices failed to catch on. The Smart Scroll and Smart Pause features in Samsung's Galaxy S4 enable navigation via face movements.