Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Card from a congregant at the Holy Angels Parish. The front cover contains a stock illustration of a haloed dove flying in front of Noah's ark. The inside reads: "I'm so sorry for you this is terrible the synagogue was bad. You're in my prayers!! Sincerely, Emma Pack , Holy Angels, Grade 4." Spelling errors corrected for clarity. Color bleeding due to water exposure at the memorial site.

Card made by a student from the George Washington University Hillel. Card reads: "We love you and are thinking of you. May we all see better days ahead. Love, GW Hillel."

Card addressed to David Rosenthal, written using personal details from various public sources.

Card made by a student from the George Washington University Hillel. The front cover contains an illustrated heart. The inside reads: "We stand with you. You are in our thoughts and prayers. With love, Leah and Molly from GW."

Card from a congregant at the Holy Angels Parish. The front cover contains a stock illustration of a haloed dove flying in front of Noah's ark. The inside reads: "I'm sorry for your loss. Jayden."

Card addressed to the Fienberg family from a family in Miami, Fl. Joyce Fienberg was a victim of the October 27 attack.

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside contains messages of prayer, unity, and love. The church's contact information is included on the back of the envelope.

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside reads: "Dear You, I have so much I could tell you, but what I want to share with you is a feeling. I want you to always feel God's love for you! I know sometimes (many times) God's love feels hidden. Where is love's light in our times of darkness? Two things help me to remember God's love each day. I hope that they can help you too.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside affirms the sender's belief that we are all God's children. The church's contact information is included on the back of the envelope.

Folded card with handwritten messages on white paper. The front cover reads: "Love," written in colorful bubble letters. The inside reads: "Your brothers and sisters in Aspinwall love you very much."

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of a flower with geometric motifs. The back contains a handwritten note, as well as a partial stock signature: "From your friends at West Allegheny Middle School."

Folded card with marker illustration. Cover features illustration of Star of David inside heart under name "Aden." Interior features illustration of five balloons and words, "We want you to know that you are not alone. Sending warm thoughts and hugs to your community. Beth Chai."

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.