item_t *items;
/* Support sequential introduction of items from bin 0 */
category_order_t order;
/* Support categories where responses are timed (0.0 == disable). */
double time_limit;
item_t *items;
/* Support sequential introduction of items from bin 0 */
category_order_t order;
/* Support categories where responses are timed (0.0 == disable). */
double time_limit;
/* Support challenges of non-text types (image, audio, etc.) */
char *challenge_type;
/* Whether to repeat afterwards (for a little extra reinforcement) */
/* Support challenges of non-text types (image, audio, etc.) */
char *challenge_type;
/* Whether to repeat afterwards (for a little extra reinforcement) */