Using positional parameters in bash scripts

#!/bin/bash
#===============================================================================
#
# FILE: posi_param.sh
#
# USAGE: ./posi_param.sh 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
#
# DESCRIPTION: To exhibit usage of positional parameters
#
# OPTIONS: ---
# REQUIREMENTS: ---
# BUGS: ---
# NOTES: ---
# AUTHOR: Parag Kalra (), paragkalra@gmail.com, www.paragkalra.com
# COMPANY: As of now Persistent System LTD, www.persistentsys.com
# VERSION: 1.0
# CREATED: Sunday 01 February 2009 01:35:54 IST IST
# REVISION: ---
#===============================================================================

echo -e "\n \n"

echo "The arguments passed are: $*"
echo -e "Total number of arguments passed are: $# \n \n"

echo $1
echo $2
echo $3
echo $4
echo $5
echo $6
echo $7
echo $8
echo $9

echo -e "\n \n"
#-------------------------------------------------------------------------------
# Accessing positional parameters with curly braces produce unexpected result
#-------------------------------------------------------------------------------
echo $10
echo $11
echo $12
echo $13
echo $14
echo $15
echo -e "\n \n"

#-------------------------------------------------------------------------------
# This is the way to access double digit positional parameters
#-------------------------------------------------------------------------------
echo ${10}
echo ${11}
echo ${12}
echo ${13}
echo ${14}
echo ${15}
echo -e "\n \n"

#-------------------------------------------------------------------------------
# This is strange
#-------------------------------------------------------------------------------
for a in 1 2 3 4 5
do
echo $`echo $a`
done
echo -e "\n \n"

#-------------------------------------------------------------------------------
# and it still remains strange
#-------------------------------------------------------------------------------
for a in 1 2 3 4 5
do
echo "$`echo $a`"
done
echo -e "\n \n"

#-------------------------------------------------------------------------------
# Shiting the positional parameters
#-------------------------------------------------------------------------------
#: << COMMENTED
echo "Shifting positional parameters.."
until [ -z $1 ]
do
echo $1
shift
done
echo -e "\n \n"
#COMMENTED

#-------------------------------------------------------------------------------
# Shiting the positional parameters by 5 characters
#-------------------------------------------------------------------------------
echo "Shifting positional parameters by 4 characters.."
until [ -z $1 ]
do
echo $1
shift 4
done
echo -e "\n \n"