Trouble with sudoku game in python 3.3.4

Question

No offense intended, but your code was just too complex to understand easily. Below is an optimized version of what you are trying to do. It is not a complete solution, however, because a Sudoku game apparently cannot be created completely randomly as this program illustrates. I hope what you can take from this is not the solution as handed to you, but a means to understand how math, loops, and functions can aid in readability, optimization, and simplicity. Try to understand what I did here and not simply use it. Then, perhaps you can further find ways to improve it to actually do what you want to do. It does solve your '1' problem though. It just may not solve your 5 and up problem :-D. Good luck and I hope this helps!!

#sudoku game
from random import randint

#generate board
def build_board():
    board=[]
    for i in range(9):
        block=[[" "," "," "],
               [" "," "," "],
               [" "," "," "]]
        board.append(block)
    return board


##
## Ensure no other block in the same row has the value
##
def row_available(block, row, board, num):
    # Determine which of the main 3 rows this 3x3 block is at
    boardRow = int(block / 3);
    good = True
    for b in range(boardRow * 3, (boardRow * 3) + 3):
        if b != block:
            if num in board[b][row]:
                good = False
                break
    return good


##
## Ensure no other block in the same col has the value
##
def col_available(block, row, col, board, num):
    # Determine which of the main 3 columns this 3x3 block is at
    boardCol = block % 3;
    good = True
    for b in (boardCol, boardCol + 3, boardCol + 6):
        if b != block:
            if num == board[b][row][col]:
                good = False
                break
    return good


def fill_board(board):
    # to fill all numbers 1 through 9
    for num in range(1,10):
        # for each of the 9 3x3 blocks
        for block in range(len(board)):
            triedRow = [-1]
            foundSpot = False
            for i in range(3):
                row = -1
                while row in triedRow:
                    row = randint(0,2)
                triedRow.append(row)
                if " " in board[block][row] and row_available(block, row, board, num):
                    triedCol = [-1]
                    for j in range(3):
                        col = -1
                        while col in triedCol:
                            col = randint(0,2)
                        triedCol.append(col)
                        if " " == board[block][row][col] and col_available(block, row, col, board, num):
                            board[block][row][col] = num
                            foundSpot = True
                        if foundSpot:
                            break
                if foundSpot:
                    break
            if not foundSpot:
                print("Never Found a Spot for " + str(num) + " in block " + str(block))
    return board


#display board
def display(board):
    num=[]
    for i in board: #block level
        for subI in i: #row
            for subsubI in subI: #item
                num.append(subsubI)
    print("---------------------------------------")
    print("| {} | {} | {} || {} | {} | {} || {} | {} | {} |".format(num[0],num[1],num[2],num[9],num[10],num[11],num[18],num[19],num[20]))
    print("---------------------------------------")
    print("| {} | {} | {} || {} | {} | {} || {} | {} | {} |".format(num[3],num[4],num[5],num[12],num[13],num[14],num[21],num[22],num[23]))
    print("---------------------------------------")
    print("| {} | {} | {} || {} | {} | {} || {} | {} | {} |".format(num[6],num[7],num[8],num[15],num[16],num[17],num[24],num[25],num[26]))
    print("---------------------------------------")
    print("---------------------------------------")
    print("| {} | {} | {} || {} | {} | {} || {} | {} | {} |".format(num[27],num[28],num[29],num[36],num[37],num[38],num[45],num[46],num[47]))
    print("---------------------------------------")
    print("| {} | {} | {} || {} | {} | {} || {} | {} | {} |".format(num[30],num[31],num[32],num[39],num[40],num[41],num[48],num[49],num[50]))
    print("---------------------------------------")
    print("| {} | {} | {} || {} | {} | {} || {} | {} | {} |".format(num[33],num[34],num[35],num[42],num[43],num[44],num[51],num[52],num[53]))
    print("---------------------------------------")
    print("---------------------------------------")
    print("| {} | {} | {} || {} | {} | {} || {} | {} | {} |".format(num[54],num[55],num[56],num[63],num[64],num[65],num[72],num[73],num[74]))
    print("---------------------------------------")
    print("| {} | {} | {} || {} | {} | {} || {} | {} | {} |".format(num[57],num[58],num[59],num[66],num[67],num[68],num[75],num[76],num[77]))
    print("---------------------------------------")
    print("| {} | {} | {} || {} | {} | {} || {} | {} | {} |".format(num[60],num[61],num[62],num[69],num[70],num[71],num[78],num[79],num[80]))
    print("---------------------------------------")  

#test
board=build_board()
board=fill_board(board)
display=display(board)

Typical Output:

Never Found a Spot for 5 in block 5
Never Found a Spot for 9 in block 4
---------------------------------------
| 7 | 9 | 1 || 4 | 6 | 8 || 5 | 3 | 2 |
---------------------------------------
| 6 | 8 | 3 || 2 | 5 | 9 || 4 | 1 | 7 |
---------------------------------------
| 2 | 5 | 4 || 3 | 7 | 1 || 8 | 6 | 9 |
---------------------------------------
---------------------------------------
| 3 | 2 | 9 || 7 | 8 |   || 6 | 4 | 1 |
---------------------------------------
| 1 | 7 | 6 || 5 | 3 | 4 || 9 | 8 | 2 |
---------------------------------------
| 8 | 4 | 5 || 6 | 1 | 2 ||   | 7 | 3 |
---------------------------------------
---------------------------------------
| 4 | 3 | 6 || 5 | 9 | 2 || 7 | 1 | 8 |
---------------------------------------
| 5 | 1 | 2 || 3 | 7 | 8 || 6 | 9 | 4 |
---------------------------------------
| 7 | 9 | 8 || 1 | 6 | 4 || 5 | 3 | 2 |
---------------------------------------