/*Logic*/
	float frameTime = 0;
	    
	//While the frame hasn't finished
	while( roundf( frameTime, 5 ) < 1 )
	{
            //Next collision time and collision intervals
            ColEvent nextEvent;
            
            //Check box collision
            for( int c = 0; c < NUM_BOXES; c++ )
            {
                //Against walls
                for( int w = 0; w < NUM_WALLS; w++ )
                {
                    //Test for collision
                    ColIntervals colI = calc_intervals( boxes[ c ], walls[ w ] );
                    float colT = col_time( colI );
                
                    //If time is earlier
                    if( colT < nextEvent.time )
                    {
                        //Replace collision event
                        nextEvent.time = colT;
                        nextEvent.intervals = colI;
                        nextEvent.a = &boxes[ c ];
                        nextEvent.b = &walls[ w ];
                    }
                }
            }
            
            //If collision happens this frame
            if( roundf( nextEvent.time + frameTime, 5 ) < 1 )
            {
                //Move to collision point
                for( int b = 0; b < NUM_BOXES; b++ )
                {
                    boxes.move( nextEvent.time );
                }
                
                <span class="cpp-comment">//Handle collision</span>
                nextEvent.a-&gt;handle_collision( nextEvent.intervals );
                
                <span class="cpp-comment">//Move time forward</span>
                frameTime += nextEvent.time;
            }
            <span class="cpp-keyword">else</span>
            {
                <span class="cpp-comment">//Do movement for remaining frame</span>
                nextEvent.time = <span class="cpp-number">1</span> - frameTime;
                
                <span class="cpp-comment">//Move to end of frame time</span>
                <span class="cpp-keyword">for</span>( <span class="cpp-keyword">int</span> b = <span class="cpp-number">0</span>; b &lt; NUM_BOXES; b++ )
                {
                    boxes.move( nextEvent.time );
                }
                
                <span class="cpp-comment">//Break loop</span>
                frameTime = <span class="cpp-number">2</span>;
            }
        }
    }

</pre></div><!–ENDSCRIPT–>

Handling two objects bouncing against each other is easy, all my boxes are assumed to have the same mass so they just exchange linear velocities to conserve momentum.

But what do I do if all of my boxes hit each other as &#111;ne clump at the same time? How would I handle if half hit each other in &#111;ne clump and the other half in another clump? And how would I handle a clump of boxes colliding at a wall?