My head is round

wǒ de tóu shì yuánxíng

My hat is triangle

wǒ de màozi shì sānjiǎoxíng

My body is square

wǒ de shēntǐ shì zhèngfāngxíng

My arms are rectangle

wǒ de shǒubì shì chángfāngxíng

My legs are also rectangle

wǒ de tuǐ yě shì chángfāngxíng

My hands are diamond (shape)

wǒ de shǒu shì língxíng

My feet are oval

wǒ de jiǎo shì tuǒyuánxíng

My name is Mr. Shapey

wǒ de míngzi jiào xíngzhuàng xiānsheng