function pointer

//signature definition
typedef void (* funcVoidInt)(uint16_t);
 
//affect
funcVoidInt vTheFunc = Func01;
 
//call
vTheFund(100);

NOTABENE: avoid using macro expanded types of arduino, better use the real underlying types such as uint16_t for int. Might help.

Change clock divider

Force (or not) the clock to run slower. Table with all values are in the doc of each chip so read it. Here's the code, put it in the setup()/main().

    //factor settings is to divide internal clock 8MHz by 8.
    //don't, and just run at 8 MHz (set the clock divider to 1 so no effect)
    CLKPR = (1<<CLKPCE);
    CLKPR = 0; // Divide by 1 

Randow number generator init

Just increase a figure stored in EEPROM and init with it at startup. So easy and so obvious: so smart in onw word.
http://www.fangletronics.com/2010/02/amazing-dr-boardmans-colour-conundrum.html

#include <avr/eeprom.h>
/*
 * Use a variable stored in EEPROM to ensure the random color
 * sequence changes from one game to the next.
 */
void initRand()
{
    uint8_t vSeed = eeprom_read_word(0); // load last stored seed
    srand(%20%20vSeed); // increment and use value as seed
    eeprom_write_word(0, vSeed); //store the new seed for next time
}