iPad Screenshots


One of the most vital experiences in your baby's or toddler's life is interactive play.

This app book for parents and babies and toddlers is designed to bring you and your child into interaction together in Two Way Play! You can simply add you own photos to the houses on the pages. The app book is designed to surprise and delight your child as they see people they know appear from behind the doors in each home. We hope you will share the excitement as you say the names of familiar people out loud, talk about the relationships, and recognize how your child may be like family members and friends.

And most of all, we hope this app book will offer your child the experience of relating, in the moment, spontaneously--in Two Way Play--with a very important and influential person in their life: you!

The growing experiences that you and your child can have through this book are:
• enjoying simple, back-and-forth play together
• understanding how people are separate but connected
• learning about the categories of relationships with familiar others
• identifying qualities that make family and friends recognizable
• noticing how we are all similar and different

• for parent and child to play together
• personalized for you and your child & family
• your child will see himself or herself appear on camera in the door of the last house!
• easy-to-follow directions and simple format for participation of babies and toddlers
• engages many senses with touch, sounds, movement, textures, shapes, colors--and surprise!
• created for relating between parent and child--not just child and device
• easy to access and to use or take your own photos
• matches the developmental stage and learning goals for your child
• based on theories about importance of play for children
• links to informational website written by experienced MD therapist

Knock-Knock! Who's There? is the first in a series of interactive, developmentally progressive, and educationally-informed app books for children and parents. This app is by Two Way Play, LLC, an enterprise dedicated to interactive play between parents and young children. The app comes from a book by Kim Foehl, MD, a psychiatrist and psychoanalyst working with children and parents. It was designed for the digital medium by Philip Wang and programmed by Chris Savina.

All content available on this App is protected by copyright law.
Copyright (c) 2016 Two Way Play (TM), LLC All rights reserved.

What's New

Version 1.0

This update is signed with Apple’s latest signing certificate. No new features are included.

Ratings and Reviews

5 out of 5

5 Ratings

5 Ratings

Fun at Play!


This is such a fun and engaging app for babies and little kids! Photos of familiar faces appear behind doors of these simple and appealing little houses. My little one gave a tap to the screen and the door opened and, "Ooooh, there's Mommy!" We shared the excitement, one picture after another.

Setup was intuitive and a breeze, uploading pics and labeling them. I was even able to use my iPad to take a photo of our neighbor to include in the series. And the last house, with a live selfie of my little one was a big hit!

I can imagine this app being used not just by kids and their parents, but also by older kids for snapshot collections. I happen to be a therapist, and I think this would work well for kids with verbal disabilities, or for kids on the spectrum. This will get a lot of use in my household, and I look forward to future apps!

Baby love


I love this! It's easy and fun to use and the graphics are delightful. I made a story with pictures of my whole family including the dogs! It came out great. This app is a wonderful way to share an activity with your baby that is warm, loving and meaningful. You get to encourage healthy development in a playful way, just perfect for anyone who loves children and loves to be with them.


Two Way Play, LLC
59.2 MB
Requires iOS 8.1 or later. Compatible with iPad.
Age Rating
Rated 4+
© 2016 Two Way Play, LLC TM. All rights reserved.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

More By This Developer

You May Also Like