What is hidden in 3D image?

There once was a blonde who was very tired of blonde jokes and insults directed at her intelligence.

So, she cut and dyed her hair, got a make-over, got in her car, and began driving around in the country.

Suddenly, she came to a herd of sheep in the road. She stopped her car and went over to the shepherd who was tending to them.

"If I can guess the exact number of sheep here, will you let me have one?" she asked.

The shepherd, thinking this was a pretty safe bet, agreed.

"You have 171 sheep," said the blonde in triumph.

Surprised, the shepherd told her to pick out a sheep of her choice.

She looked around for a while and finally found one that she really liked.

She picked it up and was petting it when the shepherd walked over to her and asked, "if I can guess your real hair color, will you give me my sheep back?"

The blonde thought it was only fair to let him try. "You're a blonde! Now give me back my dog."