It is easy to add symbols & arrows into cards, using the following notation:
Symbols
Copyright: © /
(C)
Trademark: ™ /
(TM)
Registered Trademark: ® /
(R)
Section Sign: § /
(P)
Plus/Minus: ± /
+-
En Dash: – /
--
Em Dash: — /
---
Arrows
Leftwards arrow: ← /
<--
Rightwards arrow: → /
-->
Left-right arrow: ↔ /
<-->
Leftwards double arrow: ⇐ /
<==
Rightwards double arrow: ⇒ /
==>
Left-right double arrow: ⇔ /
<==>
Here is an example of the arrows in action with a simple chemical equation.
You can also add up and down arrows using the following unicode notation:
Upwards arrow ↑ /
↑
Downwards arrow ↓ /
↓