Help creating an asterisk and T diamond

[xxxlabradorxxx]

Hi, I need to create a T diamond mixed with asterisks, so I was hoping someone could help me with the best way to go about doing this.

Enter the length (an even number between 0 and 20): -1
Enter the length (an even number between 0 and 20): 3
Enter the length (an even number between 0 and 20): 22
Enter the length (an even number between 0 and 20): 10
Enter the char used left to the diamond: *
Enter the char used to fill the diamond: T
\TTTTTTTT/
*\TTTTTT/
**\TTTT/
***\TT/
****\/
****/\
***/TT\
**/TTTT\
*/TTTTTT\
/TTTTTTTT\