Keyboard hidden symbols

There are lots of hidden symbols in ur keyboard...for example have'nt u noticed the TM symbol,copyright symbol,registered symbol,music notes etc. To get these symbols,just hold the alt key in your keyboard and type any number on the numpad on the right of the keyboard (dont use the nums on the top of alphabets,laptop users can use 'on-screen keyboard) and leave the alt key.
Eg:

alt+O169 = ©

alt+0153 = ™
alt+0174 = ®
alt+0188 = ¼
alt+0189 = ½
alt+0190 = ¾
alt+0191 = ¿

alt+1=☺

alt+2=☻

alt+3=♥

alt+4=♦

alt+5=♣

alt+6=♠

alt+7=•

alt+8=◘

alt+9=○

alt+10=◙

alt+11=♂

alt+12=♀

alt+13=♪

alt+14=♫

alt+15=☼