You choose pretty much whatever you like to make the heating pad, but you will want to use a cotton fabric, such as a T-shirt or a pillowcase. Cotton is able to withstand high heats so this is the best choice for your fabric. Ask yourself if what you have chosen would handle being ironed a high heat as a basic guide to it's suitability. Make sure nobody is going to miss whatever you decide to use.
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One-sentence summary -- Get your chosen fabric.

Article: Set your phone or computer to alert you to check your posture. Place notes for yourself around your house, car, and office. Sometimes all it takes to keep good posture is constant reminders and reinforcement. You need to reprogram your habits just as much as you need to strengthen your back muscles. Yoga is specifically good for improving your posture. Some of the best exercises include:   The cobra. Lie on your stomach with your hands under your shoulders. Make sure you point your fingers forward. Then, keeping your elbows close to your sides, try to touch your shoulder blades together. Be sure to stabilize your back by tightening your abdominal muscles. Then, slowly lift your chest to the ceiling, making sure to keep your neck long. Use your arms for support, but your back muscles to pull you up. Hold for 10 breaths, then lower yourself. Repeat 3 times.    Child's pose: Stand on your knees with your arms above your head. Palms should be facing each other. Then, exhale and slowly move forward. Lower your forehead to the floor and stretch your arms out in front of you, pressing your palms into the floor. Hold, and then return to the starting position. Repeat six times.    Mountain Pose. Stand straight with your feet on the ground,  heels slightly apart. Be sure your weight is evenly distributed between your two feet. Lift the insides of your ankles so that your feet seem cupped. Then, extend your shoulder blades and try to touch them. Slowly release. Finally, raise your arms to the ceiling and gaze forward. These techniques should specifically focus on your abdominal and back muscles as these are the muscles that will help support your spine.   Squeeze your shoulder blades together. Pretend you're holding a ball between your shoulder blades.Try to squeeze the ball by bringing your shoulder blades together. Hold for 10 seconds. This will help stretch the front of your shoulders, which will likely be tight from poor posture. Roll your shoulders. Roll one shoulder forwards, upwards, backwards, then back down. Imagine that you are sliding your shoulder blade down your spine. Then, repeat on the other side. This will help settle your shoulders farther back than they usually settle. Stretch your chest. Find a rolled up towel or piece of fabric and stand with your legs shoulder width apart. Grip the fabric so that it is taut and your hands are also shoulder width apart. Inhale and lift your arms to shoulder height. Then, exhale and pull your arms up and back as far as you can. Hold for two inhales and exhales, then lower your arms and repeat.
Question: What is a summary of what this article is about?
Remind yourself to stand up straight. Practice Yoga. Do other exercises and stretches to improve your posture.