Why i can't put the condition of 'elif' in same line of 'if' condition in this code?

Well I am trying to print alphabet "R" using for loop and if-else condition is i dont understand that why i have to use an elif statement as i couldn't run the code using only if statement. if try to put the elif content in if it doesn't work.

a=4
b=2
for i in range(7):
    for j in range(5):
        if (j==0) or ((j==4)and (0<i<3)) or ((i==0 or i==3) and (4>j>0)) :
            print("R",end=" ")
        elif (i==a and j==b) and j>0:
            print("R",end=" ")
            a+=1
            b+=1
        else:
            print(" ",end=" ")
    print()

This code is working fine

a=4
b=2
for i in range(7):
    for j in range(5):
        if (j==0) or ((j==4)and (0<i<3)) or ((i==0 or i==3) and (4>j>0)) or ((i==a and j==b) and j>0):
            print("R",end=" ")
            a+=1
            b+=1
        else:
            print(" ",end=" ")
    print()

I cannot make R pattern with this code like below.

"""R R R R   
   R       R 
   R       R 
   R R R R   
   R   R     
   R     R   
   R       R """