There are several things I'd like to know about this passage:
And Hezekiah said to Isaiah, “What shall be the sign that the LORD will heal me, and that I shall go up to the house of the LORD on the third day?” And Isaiah said, “This shall be the sign to you from the LORD, that the LORD will do the thing that he has promised: shall the shadow go forward ten steps, or go back ten steps?” And Hezekiah answered, “It is an easy thing for the shadow to lengthen ten steps. Rather let the shadow go back ten steps.” And Isaiah the prophet called to the LORD, and he brought the shadow back ten steps, by which it had gone down on the steps of Ahaz.—2nd Kings 20:8-11 (ESV)
- What is causing the shadow?
- How did the shadow move back ten steps?
- Why was it easier to go backward than forward?
- Why did Hezekiah need a sign in the first place?
The commentators assert that some type of sundial was implied, but I don't see where that idea comes from in the text. It looks like an educated guess.