Simple php fix

Very simple question here (am a total beginner) - i am trying to write a simple enclosing shortcode [ppt]something[/ppt] for wordpress that just simply returns what is in between the opening and closing shortcode. So, i have a simple php file with this: <?php function steve_function( $atts, $content = null ) { return $content; } add_shortcode('ppt', 'steve_function'); ?> This works fine. However, the trouble is that i have other basic shortcodes between the enclosing [ppt][/ppt] shortcodes. e.g. [sc1] and [sc2] which normally return lets say "output1" and "output2". However, when i have them in between my ppt shortcode, e.g. [ppt][sc1] something [sc2][/ppt] Instead of getting the result: "output1 something output2", i get the result: [sc1] something [sc2] What is wrong with my simple function - can i make it so that it outputs the results of the shortcodes [sc1] and [sc2] instead?