Pr shapes in square

#include <stdio.h>
#define SQUARE 20
#define INSIDE 10
#define SQUARE2 40
#define INSIDE2 20

//print shapes inside of square
//what to do to make it much more complicated?

void pr_sq_ins(int,int);
int main()
{
    pr_sq_ins(SQUARE,INSIDE);
    pr_sq_ins(SQUARE2,INSIDE2);

    return 0;
}

void pr_sq_ins(int sq, int ins)
{
    int i,j,k=0;
    int gap = 5;
    for(i=0;i<sq;i++)//before inside square
    {
        if((i%2)&&i>=gap&&i<sq-gap)
            k=k+3;
        else if(!(i%2)&&i>=gap&&i<sq-gap)
            k=k-3;
        for(j=0;j<sq;j++)//prints the whole row
        {
            if((i>=0&&i<gap)  ||(i>=sq-gap&&i<sq)||
               (j>=0&&j<gap+k)||(j>=sq-gap-k&&j<sq))//*one more here!
                printf("*");
            else
                printf(" ");
        }
        printf("\n");
    }
}